Update docs:

- Some comments in hip_hcc.cpp
 - document hipHostRegister* flags.
 - expand docs on hipHostRegister/Unregister. Use "register" rather than
   "pin" to describe action these take.
 - change required CUDA version to 6 (require unified memory)
 - remake doxygen.

hipamd/docs/RuntimeAPI/html/search/all_e.js

@@ -1,4 +1,5 @@
 var searchData=
 [
-  ['regsperblock',['regsPerBlock',['../structhipDeviceProp__t.html#a73c1c21648a901799ff6bef83c11135b',1,'hipDeviceProp_t']]]
+  ['pcibusid',['pciBusID',['../structhipDeviceProp__t.html#a1350f64d49b717ed3a06458f7549ccb0',1,'hipDeviceProp_t']]],
+  ['pcideviceid',['pciDeviceID',['../structhipDeviceProp__t.html#ae6aa845dc2d540f85098ea30be35f4eb',1,'hipDeviceProp_t']]]
 ];