Rewrote integration to be more transparent with regards to changes. Preparing for completely adaptive mass step.
Removed superflous comment.
Too tiny dm causes rho to go to zero after 1 step.

Currently in process of fixing dynamic mass step. Problem is not in decision of new step but in that smaller dm than -1e24 makes rho go to zero after one step.

* Fixed calculation of rho from EOS - is now explicit variable in integration scheme.