Backlog v0.2

Changelog:

• A lot of bugfixes (look at commits for details)
• Features/enhancements:
  • Hide unwanted games
  • Settings page
    • Customize statuses
    • Truncate database
    • Unhide games
  • Orphaned games scope
  • No Steam sync after every purchase add
  • Import games with non-zero playtime as "started playing" by default
  • History page with date
  • Steam profile widget
  • Multiple Steam operations with one API request (faster)
  • Replaced history with shop shares
  • Default date for adding purchases is now today
  • Hint for syncing with Steam after adding games
• Technical stuff:
  • Switched to prepared statements
  • Javascript in seperate files
  • Support for multiple libraries per page
  • Several HTML validation and semantic fixes