Helps with large libraries when running the downloader multiple times.
Getting game details for many games takes a long time. Caching the game details makes the process much faster for subsequent runs.
Game details are cached to "$XDG_CACHE_HOME/lgogdownloader/gamedetails.json"
--update-cache creates and updates the cache.
--use-cache enables loading game details from cache.
--cache-valid specifies how long cached game details are considered valid
Version check before download now works without local XML data. However it is much slower without the XML data because it calculates MD5 for the files
Some changes to config.h
- Removed "bHelp" from config because it was not needed
- Changed "bNoColor" to "bColor"
- Changed "bNoUnicode" to "bUnicode"
