Fixed some issues in odesolver.cpp
Fixed a remaining issue in ticket #520
Implemented ticket #521 "Enhance the 'cmp()' function"
Fixed issue #520 "Enable '\times' in plot legends and labels"
Small fixes
Fixed a small issue in implementation of ticket #517
Implemented ticket #519 "Enhance plotting features"
Implemented ticket #518 "Create an 'implot' command"
Added new matop function 'shuffle()' and inserted many DoxyGen comments
Multiple fixes for procedures