added secure shared prefs submodule
added new submdodule to gradle, forced crashlytics plugin to version 1.0.6 to work around ProGuard bug
Added helper class to identifie the specific app installation
ignore config file containing the private encryption key
moved the login check to start of activity, check for secure saved credentials

If the app is updated and used the unsecure credentials bevor, they
will get cleared and the user has to sign in again
moved from shitty unencrypted SharedPrefs to awesome encrypted SecurePrefs
???
Merge branch 'shared-prefs-crypto'
added secure shared prefs submodule
added new submdodule to gradle, forced crashlytics plugin to version 1.0.6 to work around ProGuard bug
Added helper class to identifie the specific app installation
ignore config file containing the private encryption key
moved the login check to start of activity, check for secure saved credentials

If the app is updated and used the unsecure credentials bevor, they
will get cleared and the user has to sign in again
moved from shitty unencrypted SharedPrefs to awesome encrypted SecurePrefs
???
created new main menu
moved useful activity stuff here, needs to be split up
new about activity
Moved some Stuff from Main Menu to OptionsMenu
Created options menu for about and feedback