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.

docs/RuntimeAPI/html/search/classes_3.js

@@ -1,5 +1,8 @@
 var searchData=
 [
-  ['texture',['texture',['../structtexture.html',1,'']]],
-  ['texturereference',['textureReference',['../structtextureReference.html',1,'']]]
+  ['ihipdevice_5ft',['ihipDevice_t',['../structihipDevice__t.html',1,'']]],
+  ['ihipevent_5ft',['ihipEvent_t',['../structihipEvent__t.html',1,'']]],
+  ['ihipexception',['ihipException',['../classihipException.html',1,'']]],
+  ['ihipsignal_5ft',['ihipSignal_t',['../structihipSignal__t.html',1,'']]],
+  ['ihipstream_5ft',['ihipStream_t',['../classihipStream__t.html',1,'']]]
 ];