Parse podcast duration correctly even with trailing whitespace

The Skeptoid podcast (available on gpodder.net) currently has a specific
episode (titled "Skeptoid #437: Tube Amplifiers") that contains the XML
<itunes:duration>14:57 </itunes:duration> which AntennaPod fails
to parse (and instead hits a java.lang.NumberFormatException which
it prints to stderr every time the refresh button is pressed).
The duration for that particular episode is not correctly showed in
the UI, although the duration for other Skeptoid episodes show up
just fine.
Updated dependencies

Removed unused dependencies
Prepared release of next version
Avoid loading Chapters of multiple FeedItems at the same time

This should significantly reduce the time needed to load FeedItem lists with chapters, because chapters are from now on only loaded when a single FeedItem is requested.
Fixed fullscreen issues in video player

Affects issue #563
Destroy webview when it is no longer used

Not destroying the webview might have caused crashes on some devices
Use isNotBlank instead of isNoneBlank

Caused NoSuchMethodError on some devices
Bugfix: Seconds in RFC822 are optional

fixes #545
Handle protocol relative URLs correctly when downloading episodes and images

fixes #568
Changelog update
Replaced '-' with '*'

fixes #572
Merge branch 'skeptoid_duration_parse_error' of git://github.com/mo/AntennaPod into mo-skeptoid_duration_parse_error
Pulled translations
Video overlay was hidden in some cases
Upgraded dependencies

Flattr4j has been upgraded to 2.12. This version makes it possible to use flattr on Android 2.3 devices.
Improved look of ItemlistFragment header
Updated audio player layout
Moved settings button into navigation drawer
Use toolbar in MainActivity instead of actionbar
Use 2-line TextView in AudioplayerActivity toolbar