HeliBoard 1.2

Changes since 1.0:

• new signing key: unfortunately you will have to backup your settings and uninstall the app before you can install v1.2, see #624
• fix haptic and audio feedback (#597, #602, #604, #606, #607, #608, #609, #610, #612, #615, #617, #620, #621, #622, #623, #625)
• avoid adding clips to clipboard history multiple times

This is the same version as now deleted 1.1 was, just with correct version number. Just updating 1.1 APKs would have created issues with incoming F-Droid build.