Fixing some problems with type casting.
Another fix to the nexus writer to print only the taxa that are included.
Some more work on partial likelihood scaling.
Better type conversion.
Merge branch 'development' of https://github.com/revbayes/revbayes into development

Conflicts:
	src/revlanguage/functions/argumentrules/ArgumentRule.cpp
More fixes for argument rules and type conversion.
Merge branch 'development' of https://github.com/revbayes/revbayes into development