Making checks consistent.
Do simplification of solution before printing solver info.
Show figures when open figures button is pressed in IVP mode.
Fixing 'invalid tolerance' bug after pressing clear all.

Turns out that the CHEBGUI constructor was initialising the .tol
field of CHEBGUI objects as a scalar, rather than a string like
the actual gui prefers.
Throw meaningful error if we try to solve PDE in incorrect mode.
Merge branch 'feature-firstOrder-reform' into fix-chebgui-IVPs