Don't leave lone closing parens.
Use double semicolon comments.
Reindent ninja-mode.el using Emacs.

Emacs knows best how to indent Emacs Lisp.
Use quasi-quoting instead of list+cons.
Set comment-start buffer-locally, not globally.
Set up a proper syntax table for ninja-mode.

Since quotes are not meant to be treated as string delimiters,
the syntax table is the place to tell Emacs so.

This also means syntactic fontification can be reenabled and the
font-lock keyword entry for comments removed.
Correctly recognize comments.
Remove unnecessary regexp group.
Don't use dotted list syntax unless necessary.
Avoid putting properties past the end of the buffer.
Correctly recognize a comment if the previous line is a comment ending in $.
Add a Emacs 24 requirement.

Only Emacs >= 24 has prog-mode.
Use lexical-binding.

There's no reason not to use lexical-binding when supporting only
Emacs 24+. Its semantics are just that much saner.
Merge pull request #864 from Fanael/ninja-mode.el-refactor

Ninja mode.el refactor