Config dir migration on Unix.
|Reported by:||verm||Owned by:||Plorkyeran|
The config dir on Unix is ~/.aegisub-<major>.<minor> (eg ~/.aegisub-2.2/)
When upgrading from a previous version to a new version this needs to be handled correctly. In most cases this just means copying the contents of the old dir to a new one and letting aegisub handle it as it normally would on Windows or OS X.