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/classes_4.js

@@ -1,7 +1,4 @@
 var searchData=
 [
-  ['ihipdevice_5ft',['ihipDevice_t',['../structihipDevice__t.html',1,'']]],
-  ['ihipevent_5ft',['ihipEvent_t',['../structihipEvent__t.html',1,'']]],
-  ['ihipstream_5ft',['ihipStream_t',['../structihipStream__t.html',1,'']]],
-  ['int1',['int1',['../structint1.html',1,'']]]
+  ['stagingbuffer',['StagingBuffer',['../structStagingBuffer.html',1,'']]]
 ];