Merge tag '0.11' into develop

New format for questions: mainly ordering tweaks, and optional hints and skipping of questions
Set back average interval between questions to 2 hours
Bump version of compatibility library
Add debug info for Travis
Update build-tools and sdk versions
Fix compatibility library version and remove debug info for Travis
Add a release checklist and a list of grammar versions used
Typo and phrasing
Update travis-ci links
Update changelog and release instructions
Update build and contribution configuration
Update contributing instructions
Updates some dependency versions
Tentative fix for travis build
Ui changes for prod/test mode: added save variable current mode and interface for mode switch. Beginning of theme change
implemented change in background (dashboard only) when mode is changed
background managing multiple profiles
correction : only reseting test profile
correction : only reseting test profile at switch prod to test
CryptoStorage adapts itself to the profile used