xplanet 1.3 (updated dependencies added)

Adding a "complete" option so that the necessary dependencies installed with Xplanet match Xplanet's default configuration options, namely: PNM support via netpbm, TrueType support via freetype, and PANGOFT2 support via pango.  This will not include JPLs CSPICE library since that is not a current formula.  Assuming theuser has followed the instructions to install and link CSPICE in Homebrew, this updated formula will include support for that as well.