Allow settings and cache to be saved in arbitrary location

[JavLuv]

This feature will allow multiple machines to share a single collection, and enable portable app support.

I'll need to split settings into local and shared settings. Obviously, local settings are stored in the same location as currently. It will also point to the shared settings file, which will default to where local settings are stored. Will need to consider which settings belong locally and which should be shared.

Issues to deal with:

• The user can't be allowed to edit the data simultaneously on multiple machines.
• The user will be required to keep their versions of JavLuv synced, or otherwise data loss could occur, even if only in settings.
• Will need to split out path root into local settings, in case a network drive is mapped X: on one machine and Y: on another