Merge pull request #233 from eggrobin/body-accessor

Add accessor to for body Celestial
I CAN HAZ TEH const
Merge pull request #227 from eggrobin/plot-trajectories

Plot trajectories
base
First draft
optimize factory
Change the return type and fix a broken test.
split body
Incorrect accuracy.
This totally looks like a bug in VS2013 (see 12.2/5).
After egg's review.
Merge pull request #236 from pleroy/CoordinatesByRef

Change the return type of coordinates() and fix a broken test.
Template specialization time!
Specialize...
That's a solution, I guess...
better
Minor changes.
comments
true != false
Reordering