Use lua generator in place of ex_cmds_defs header trick

Closes #788
Fixes #379
Ref #549
Add const qualifier and explicit length
Fix problem with test47: addition is not bitwise OR

:diffsplit command used to include some flag value twice. If I was using bitwise
OR it would be OK, but I had addition here. Changed to use bitwise OR.
Extend documentation
Merge pull request #840 from ZyX-I/generate-ex_cmds

Use lua generator in place of ex_cmds_defs header trick
vim-patch:7.4.296

Problem:    Can't run tests on Solaris.
Solution:   Change the way VIMRUNTIME is set. (Laurent Blume)

https://code.google.com/p/vim/source/detail?r=v7-4-296
vim-patch:7.4.339

Problem:    Local function is available globally.
Solution:   Add "static".

https://code.google.com/p/vim/source/detail?r=v7-4-339
Merge pull request #1100 from atwupack/vp-7.4.296

vim-patch:7.4.296
Merge pull request #1101 from atwupack/vp-7.4.339

vim-patch:7.4.339
Mark patches 176, 185 and 189 as NA
Merge pull request #1103 from Hinidu/na-patches

Mark patches 176, 185 and 189 as NA