Populate .gitignore with more files

Shouldn't `composer.lock` and `logs` be on `.gitignore`? Also, previous versions of CakePHP had the IDE and OS parts which I copied here (adding `*.sublime-*` for sublime dotfiles).
Removed IDE and OS

Leaving only `/composer.lock` and `/logs/*` as additions.
Merge pull request #119 from elboletaire/patch-2

Populate .gitignore with more files