Brewfile: Install PHP 5.5 with GMP support
.osx: Don’t show hidden files by default

Most of the time I don’t need it, and when I do, I can temporarily enable it using the `show` alias, and revert it using the `hide` alias.
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  .osx: Don’t show hidden files by default
  Brewfile: Install PHP 5.5 with GMP support
Change to new PHP Homebrew tap