Support for ocontexts per device.

ocontexts was split up into 4 files:
1.fs_use
2.genfs_contexts
3.initial_sid_contexts
4.port_contexts

Each file has their respective declerations in them.
Devices, in their respective device directory, can now specify sepolicy.fs_use, sepolicy.genfs_contexts, sepolicy.port_contexts, and sepolicy.initial_sid_contexts. These declerations will be added right behind their respective sepolicy counterparts in the concatenated configuration file.