Add append_args setting

[blueyed]

Fixes https://github.com/neomake/neomake/pull/1003.

TODO:

• [ ] feedback
• [ ] doc
• [ ] check how this interacts with append_file=0/1 and via InitForJob (tests)

[augusto67ovi]

Hi man, I just need some help with this new function I need to specify some args to the maker I'm using but still I don´t know how. I am using Pylint

let g:neomake_python_enabled_makers =['pylint'] '--disable=W0107,W0410,W0611,W0613,W0614,C0103,C0301,C0302,R0902,R0914,R0913,R0904,R09034'

Please, how can I achieve that using my init.vim file?

`

[blueyed]

@augusto67ovi When using this PR/branch it would be let g:neomake_python_pylint_append_args = '--disable=W0107,W0410,W0611,W0613,W0614,C0103,C0301,C0302,R0902,R0914,R0913,R0904,R09034'.