Bug fixes

445d6bc Added explainer for Incognito mode
fd1c999 Fix disappearing system toolbar (white on white)
a1d63a2 Hide empty alias in account info fragment
7359174 Ensure CONTACTS permission is not revoked before use
a3a517f Better check for permissions when AudioOnly is true
834d17b Fix for tinode/chat#950
7598835 854f846 Load emoji font and initialize EmojiCompat library
f90ff2a Better emoji counting code - use com.ibm.icu instead of android.icu
c813c54 More unit tests

Full Changelog: v0.24.0...v0.24.2