64bit inline asm

Add 64bit asm code for Linux and Darwin to the functions that already
have darwin32 code.
A quick little fix or this #if won't work correctly
Sligth modifications as per suggestions from breznak
Unify linux64 and darwin64 cpuid

Shouldn't have been saving the id directly to a memory location.
reproduce #48
Recover `zlib.h` files from numenta:master@46835bfdf53b4b2d12f88ed1fd0dd02f33bf22aa
Remove reproduction of #48 after fixed it
Merge branch 'master' of https://github.com/numenta/nupic.core into 48-zlib
Merge remote branch 'upstream/master' into 64bit-asm
Merge pull request #97 from utensil/48-zlib

Recover `zlib.h` in `external`
Remove custom stylesheet, fall back to default because qmi isn't compatible with Doxygen 1.8.7
Merge branch 'master' of https://github.com/numenta/nupic.core into 80-engine-api-doc
Merge pull request #100 from utensil/80-engine-api-doc

Remove custom stylesheet, fall back to default because qmi isn't compatible with Doxygen 1.8.7
Spatial Pooler Doc Update
Spatial Pooler Doc Update
Spatial Pooler Doc Update
Spatial Pooler Doc Update
Spatial Pooler Doc Update
Improve doc of types
Doxyfile tweaks: fix casing and enable STL support