MemMap: Renamed "GSP" heap to "linear", as this is not specific to GSP.

- Linear simply indicates that the mapped physical address is always MappedVAddr+0x0C000000, thus this memory can be used for hardware devices' DMA (such as the GPU).
Common: Add "sysdata" to GetUserPath and cleanup.
APT_U: Added GetSharedFont service function.
Merge pull request #267 from bunnei/apt-shared-font

APT shared font loading