Program Database & Archive Library

[sirjuddington]

This (WIP) branch/pr adds a SLADE program database for storing various data, info and settings that don't really belong in user-editable text files.

A basic overview of what is saved to the database (so far):

• Info about each Archive opened
  • Entries (type, hash, etc.)
  • Maps
• UI state
  • Window layouts and sizes (instead of in .layout files and slade3.cfg)
  • Entry list configuration (per-archive)
• Run dialog settings (per-archive)
• Map editor configuration (port, game etc.) (per-archive)
• Bookmarked entries

This also adds an archive library UI which lists all previously opened archives and allows opening or running them directly

I'm not 100% sure about going ahead with merging this for 3.3.0 since there is potential to introduce a whole new class of bugs :P However there are also many big improvements it could lead to such as simplifying and extending the undo/redo system, or potentially even recovering data after a crash.

Planned/potential additions:

• Save basic map data to make loading map previews faster (especially for UDMF maps)
  • Potentially could expand this to full map data, again to improve opening time of UDMF maps in the map editor
• Save parsed zscript, especially from (g)zdoom.pk3 which shouldn't change often, currently it's re-parsed every time
• Replace Undo/Redo system with something simpler (eg. full data backups) since we wouldn't have to worry so much about memory usage
• Store archive data for the session so it can be restored in case of a crash (possibly could just be implemented as a side effect of the above)