Update timing_model.py

param_help did not actually return the help string. Now it does
Update utils.py

If the input string was given as an integer, the conversion failed. 
There might be better solutions to the problem than the one I propose, this is mostly to raise awareness of the issue.
Update toa.py

Solves two problems: a missing ephemeris from SPICE (JUPITERBARYCENTER -> "JUPITER BARYCENTER") and a non-existing variable (plan_pvs, it was defined as plan_poss)
Merge pull request #6 from vhaasteren/master

Make pint installable
Merge pull request #5 from matteobachetti/patch-2

Update utils.py
Merge pull request #9 from matteobachetti/patch-4

Update toa.py
Merge pull request #4 from matteobachetti/patch-1

Update timing_model.py
Cleanup of warnings and some tests
planet shapiro bugfix and clock correction bugfix
Initial fitter almost working...
More fitter changes.  Started examples directory.