Changes:
- Bug fix to input.py by @dave-andersen with tests.

- Some fixes to names in the whitepaper

- Include cfloat for FLT_MAX by @benoitsteiner

- Fix broken link in mnist tutorials by @mrry

- Typos and fixes to documentation by @Sohl-Dickstein, @ebrevdo, @vrv,
  Yaroslav, @martinwicke

- Fixed unnecessary check around a delete by @girving

- More compatibility tests by @josh11b

- Misc other typos and fixes by Googlers.

Base CL: 107944070