added mag_err/uncertainty to comment line. Also moved building of comment line to mpc.MPCComment
Merge remote-tracking branch 'origin/master'
moved orbfit out of mpc file... doesn't belong here.
Added test of orbfit class.
added residual  and orbit attribute to the Orbit class.
Fixed test errors resulting from obs mag error introduction.  Skip 
test_orbfit if the .so file is not found.
Added include_comments flag to MPCWriter, updated test cases.
Merge pull request #195 from drusk/fix_tests

Fix tests
Merge branch 'master' into triplet_controllers
Moved workload module into models package.  Split the 
StatefulCollection class out into its own collections module.