Allow game database file to be loaded from a different directory.

This will allow system-wide installation of Pyfa in Python site-packages
directory, where eve.db has nothing to do.

This commit is part of attempts to ease system package creation and
maintenance (specifically Gentoo ebuilds).

config.py

@@ -96,7 +96,9 @@ def defPaths(customSavePath):
     # The database where the static EVE data from the datadump is kept.
     # This is not the standard sqlite datadump but a modified version created by eos
     # maintenance script
-    gameDB = os.path.join(pyfaPath, "eve.db")
+    gameDB = getattr(configforced, "gameDB", gameDB)
+    if not gameDB:
+        gameDB = os.path.join(pyfaPath, "eve.db")
 
     # DON'T MODIFY ANYTHING BELOW
     import eos.config