New functions are used for texture library initialization.
GetUserDataPath() returns default folder to search for hi-res texture packs.
GetUserCachePath() returns folder to store texture cache.
Mupen64Plus implementation: use system ConfigGetUserDataPath() and ConfigGetUserCachePath().
Windows implementation: just return FindPluginPath() for both functions.
Note: behaviour of Mupen64Plus changed.
Previously the emulator's folder was default path for hires textures and texture cache.
Now default path is system dependent.
For Windows it will be %HOME%\AppData\Roaming\Mupen64Plus
