This PR implements the base foundation of the code signing and integrity check. In this PR implemented is the signing and verification logic, as well as commands to sign single apps or the core repository.

Furthermore, there is a basic implementation to display problems with the code integrity on the update screen.

Code signing basically happens the following way:

- There is a ownCloud Root Certificate authority stored `resources/codesigning/root.crt` (in this PR I also ship the private key which we obviously need to change before a release ). This certificate is not intended to be used for signing directly and only is used to sign new certificates.
- Using the `integrity:sign-core` and `integrity:sign-app` commands developers can sign either the core release or a single app. The core release needs to be signed with a certificate that has a CN of `core`,  apps need to be signed with a certificate that either has a CN of `core` (shipped apps!)  or the AppID.
- The command generates a signature.json file of the following format:
```json
{
    "hashes": {
        "/filename.php": "2401fed2eea6f2c1027c482a633e8e25cd46701f811e2d2c10dc213fd95fa60e350bccbbebdccc73a042b1a2799f673fbabadc783284cc288e4f1a1eacb74e3d",
        "/lib/base.php": "55548cc16b457cd74241990cc9d3b72b6335f2e5f45eee95171da024087d114fcbc2effc3d5818a6d5d55f2ae960ab39fd0414d0c542b72a3b9e08eb21206dd9"
    },
    "certificate": "-----BEGIN CERTIFICATE-----MIIBvTCCASagAwIBAgIUPvawyqJwCwYazcv7iz16TWxfeUMwDQYJKoZIhvcNAQEF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\niG+UxI/MNcWV0uJg9S63LF8=\n-----END CERTIFICATE-----",
    "signature": "U29tZVNpZ25lZERhdGFFeGFtcGxl"
}
```
`hashes` is an array of all files in the folder with their corresponding SHA512 hashes (this is actually quite cheap to calculate), the `certificate` is the  certificate used for signing. It has to be issued by the ownCloud Root Authority and it's CN needs to be permitted to perform the required action. The `signature` is then a signature of the `hashes` which can be verified using the `certificate`.

Steps to do in other PRs, this is already a quite huge one:
- Add nag screen in case the code check fails to ensure that administrators are aware of this.
- Add code verification also to OCC upgrade and unify display code more.
- Add enforced code verification to apps shipped from the appstore with a level of "official"
- Add enfocrced code verification to apps shipped from the appstore that were already signed in a previous release
- Add some developer documentation on how devs can request their own certificate
- Check when installing ownCloud
- Add support for CRLs to allow revoking certificates

**Note:** The upgrade checks are only run when the instance has a defined release channel of `stable` (defined in `version.php`). If you want to test this, you need to change the channel thus and then generate the core signature:

```
➜  master git:(add-integrity-checker) ✗ ./occ integrity:sign-core --privateKey=resources/codesigning/core.key --certificate=resources/codesigning/core.crt
Successfully signed "core"
```

Then increase the version and you should see something like the following:

![2015-11-04_12-02-57](https://cloud.githubusercontent.com/assets/878997/10936336/6adb1d14-82ec-11e5-8f06-9a74801c9abf.png)

As you can see a failed code check will not prevent the further update. It will instead just be a notice to the admin. In a next step we will add some nag screen.

For packaging stable releases this requires the following additional steps as a last action before zipping:
1. Run `./occ integrity:sign-core` once
2. Run `./occ integrity:sign-app` _for each_ app. However, this can be simply automated using a simple foreach on the apps folder.

tail the server log and exit with the exit code of behat

Use .text instead of .html

[3rdparty] Bump php-parser

Scrutinizer Auto-Fixes

[3rdparty] Remove some unrequired files

Makes some static source code analyzers happier.

Sharing integration test 20645, added sabre dav and propfind check.

This commit consists of patches automatically generated for this project on https://scrutinizer-ci.com

Fix column width of mtime column

[3rdparty] bump jeremeamia/superclosure to 2.1.0

Fix already defined warning from dav test bootstrap

Allow DI the system tag stuff without Application class

Activity oracle sql error for favorites

Update some JS dependencies

Fix the width of the share with input

Use XMLWriter to generate response

So evaluate the condition directly and return 1 or 0

Fix ext storage mount options dropdown

* the ID of this has changed to #shareWith-viewNUMBER and shouldn't
  be used in CSS
* now uses the proper classes

* in some translations (e.g. german) the header of this column otherwise
  got truncated
  "Zeitpunkt der Freigabe" vs "Zeitpunkt der Freig"

Gets rid of manual XML generation.

Implement systemtag managers and mapper

Fix public link getDownloadUrl to return Webdav public link

Update README.md

cache resized avatars