elixir-mix.el v0.3.0 Release

• Remove compile-mode crufy at top of output
• Add font-lock stuff to highlight error or success
• Save and restore default-directory around execution of mix
• Fix save-some-buffers to not ask about save writable buffers (like term sessions)
• Fix typos

Big thanks to Dave (@pragdave) for all the work on this release. ;-)