Otherwise every time the AppStore was opened a lot of connections to the AppStore server were made which resulted in a terrible performance.

This changeset will cache the response for a sensible time so that only the first request will be somewhat slow.

Performance changes:
- Loading a category took previously more than 3 seconds on my machine. Now for every follow-up request it takes less than 200ms, resulting in a performance gain of 1950%
- Loading the category list took previously about 750ms - now it takes 154ms, a total performance gain of 395%

Otherwise the function is executed n times which is a lot of overhead

filter installed and not-installed apps properly

kill unneeded file

load category 'Installed' on page load

adding documentation links

new apps mgmt: first style adjustment

apps mgmt: only show license and preview if they exist

adding buttons

new apps mgmt: fix for mobile

use app icon if available

new apps mgmt: position enable/disable toggle to the right

new apps mgmt: proper display of icons or previews

new apps mgmt: fix loading spinner

reenable group selection for apps

new apps mgmt: position enable button normally again

new apps mgmt: clarify wording from 'Installed' to 'Enabled'

reintroduce enable/disable

Move rating image path generation to client-side

Move expression outside of l10n

fix group handling

add buttons for 'More apps' and 'Add your app' again

disable changed date of app for now

adding recommended label

style 'Recommended' app tag

fixing php warning

sort by rating

adding meta-category 'Recommended'

 Only show existing documentation links

lacy loading of screenshots

making group based app activation work again

adding support to get the app icon not only by the app name but also simply by the fixed name 'app.svg'

adding app.svg for all core apps

query string '?installed' is not longer needed

update and uninstall is back + error feedback

remove unneeded parameter

fix alignment of 'recommended' label

This can now be achieved by setting `appstoreenabled` to `false` in config.php

* test case added to avoid adding them later

Conflicts:
	lib/private/vcategories.php

This is for all LowerCaseConstant warnings

put all the calls into one function and use tabs instead of spaces. Thanks to danimo for bugging me :-)

add a sane socket timeout so that the interface stays responsive with a slow or not working internet connection

Added failsafes for retrieving remote apps on settings->apps page, in case categories or app data are not found