coq v8.3pl5.
coq v8.3pl5.

Formula is for coq v8.3pl5, the latest version of the 8.3 branch.
This is not intended to be merged in the brew master branch, but in the homebrew-versions branch.

Closes #71.

Signed-off-by: Adam Vandenberg <34c2b6407fd5a10249a15d699d40f9ed1782e98c@gmail.com>

Ashton-W/homebrew-versions,heuermh/homebrew-versions,DomT4/homebrew-versions,coeligena/homebrew-verscustomized,UniqMartin/homebrew-versions,jimhe/homebrew-versions