v0.9.0

Changes:

• Add backend support:
  • nuqql-matrixd-nio
  • nuqql-mattermostd
• Always zoom Log Window when entering and change search input
• Add logging and the "--loglevel" command line argument
• Improve backend handling
• Update backend interface documentation:
  • Add "version" command
• Cleanups, fixes, and improvements
• Requires nuqql-slixmppd v0.6.0, nuqql-matrixd v0.4.0,
  nuqql-matrixd-nio v0.1.0, nuqql-mattermostd v0.1.0, or purpled v0.5