return both, count and result if the operation succeeded or failed. Maybe in some cases it is useful to know how much bytes where copied

using the number of writen bytes as indicator if streamCopy() was successfully. Instead check if fwrite returns the number of bytes or false

When this is the case only the configured max upload size is taking into account for uploading

Simplify the code and remove a first  unnecessary (and non conform) '&' character when there are pending arguments

For Windows systems

refs #1162

otherwise /foo/bar would be detected as a subfolder of /bar

THX @icewind1991

isSubDirectory() checks if a specified $sub is a subdirectory of the
$parent, this is needed to prevent file inclusions.

Actually, the current code is more kind of a "hack" which I always
struggle over if browsing through source. So this should be a much
better implementation.

The implementation is really straightforward:
- [realpath()](http://php.net/manual/function.realpath.php) expands all
symbolic links and resolves references to '/./', '/../' and extra '/'
characters in the input path and return the canonicalized absolute
pathname.
- [strpos()](php.net/manual/function.strpos.php) returns FALSE if the
substring wasn't found.

Since this is an absolutely critical piece of code, I'd like to ensure
that this is absolutely safe!

And some documentation adjusted on the way

the maximum upload size is updated within the browser once an upload or delete operation has been finished

now should work with temp files too

Check files when copying recursivley

Remove obsolete method

Dont count '.' and '..' as directories when importing.