Minor buffer.c style cleanups
Merge pull request #998 from war1025/dev/buffer_cleanup

Minor buffer.c style cleanups
eval: re-remove USE_CR #1002

It was already removed in 01ca460 and I erroneously introduced it again in
PR #978.
Units: Move NULL, OK, and FAIL to helpers.moon. #982
eval: re-add has('mac') and has('macunix') #976

They were removed but they can be handy to separate some things to do at
startup in a .vimrc for example.
doc: Remove 'textmode'

by @mhinz
runtime: Remove 'textauto'
doc: Remove "h" flag of 'highlight' option

HLF_H is an obsolete flag and got replaced by HLF_E.

From: Marco Hinz <mh.codebro@gmail.com>
vim-patch:7.4.327

Problem:    When 'verbose' is set to display the return value of a function, may get E724 repeatedly.
Solution:   Do not give an error for verbose messages. Abort conversion to string after an error.

https://code.google.com/p/vim/source/detail?r=99d8f2d72dcd4b850de81998cc9b1120c8165762