1. Moved half device functions around so that script can catch the signatures
2. Generated docs for half precision apis
Change-Id: Iee27658e3a639fdb02af135e71841dc6427f15e2
1. Commented out unsupported device math functions
2. Moved function signatures to the top of implementation snippets
3. Added script to generate markdown documentation for device math apis
4. Added the generated file from the script which should be present everytime
Change-Id: Ic579dd8b8fdffa6e1b4d4f5f3fd8a803f4dcaac7