update formula to homebrew standard
move naming from gcc48 to gcc
Update .travis.yml
moved back to gcc48
Revert "Revert "Update GCC48 version to 4.8.3 and add boxen prefix""
Use homebrew-version dependecies
Revert "homebrew/versions is not needed anymore"

This reverts commit b7b94858c38cc4f25e09089ca947f4f4437febab.

Conflicts:
	spec/classes/gcc_spec.rb
revert to homebrew-version gcc48.rb
Merge pull request #8 from boxen/fix-gcc48-formula

Restore homebrew-versions for gcc