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
Unfinished RecyclerView
Reduced background jobs to one

This reduces one memory spike when two images are decrypted at the same
time
Fixed NPE when deleting file without thumbnail
Fixes NPE when reading file without existing file header