Add option to disable explicit solver optimisations for debugging
Move some code out of parse.py into a general python header
Initial commit of self test for odes

* Doesn't test that time step sizes chosen by adaptivity yet..
Fix bug in ode problems where initial condition was not set
Add calculation of error norm for ode problems
Improvements to odes self test

* Check ltes for 2nd order poly case

* Bound error values in adaptive by some proportinoal to the value

* Move some code into functions
Only calculate element areas if we have finite elements