added PLCrashReporter. Open E-Mail Sheet, after crash has occurred.
moving mail body generation to helper class.
don't present MailVC for Crash sending from AppDelegate, but from ViewController conforming to protocol.
Asking user prior to presenting E-Mail sheet
added CrashHandling conformity to iPad's rootviewcontroller.
purging crash report after loading.
moving MailComposeVC creation to Helper class
Merge branch 'crash-reporting'

Conflicts:
	Podfile.lock
	Wallabag.xcodeproj/project.pbxproj
preparing release: increasing version number, updating Localizable.strings file (de)