Add context null check in oncreate clauses
Merge pull request #53 from Doplgangr/NPE
Fix multiple loading results in repeated setting
Fix crashes if play store do not exist (e.g. emu)
fix drawerlayout UI -- define specific metrics to prevent unpredicted sizes.
New Acionbar icons for material design
New Action Icons for backup and restore
Merge pull request #55 from Doplgangr/SettingsScreen

Settings screen -- bug fixes
Merge pull request #56 from Doplgangr/Layouts

Layout Edits
Added RecyclerView to build.gradle
Reduced number of jobs to one

This avoids memory spikes when more than one image is decrypted at the
same time.
Fixed NPE when deleting file without thumbnail
Fixed NPE when loading file with missing header
Removed onCreate from FileViewer

onCreate seems to be never called. It further would not work anymore
because opening a file without a loaded vault would not work.
Changed list_file layout to RecyclerView
Unregister VaultListFragment from EventBus when destroyed
Changed FileList to Recyclerview
Merge pull request #57 from L-Henke/recyclerview

RecyclerView
Added missing DecryptingFileDoneEvent
Merge pull request #59 from L-Henke/recyclerview

Added missing DecryptingFileDoneEvent