#220 Add a convenience assertion asserttrue

[Chuck Castillo]

I like to do an assertion on the results of some logical functions
e.g. %sysfunc(fileexist(..args)) NE 1
%sysevalf(arg1 LT arg2)
%eval(arg1 NE )

I've written an asserttrue assertion tested in batch and interactive mode to use for these and to test other conditions in general (rather than assertEquals). I've attached a patch file for your consideration to include this in the list of assertions.

[Klaus Landwich]

Implementation finished