Fix a bug in the networking stack

Solves an networking issues when compiling with iOS 8
Improve fetching the optimal icon of an app for the update view
Fix some best app icon finding issues

In some cases the algorithm didn't find any icon, even if they are there
Update PLCrashReporter to v1.2
3.5.6 release and documentation updates
Merge branch 'hotfix/3.5.6'