Changed to more strict handling of main() - if it's not defined in main-calling mode then the program will crash rather than ignoring the problem.
Tests changed to correspond to this approach.
git-svn-id: http://picoc.googlecode.com/svn/trunk@479 21eae674-98b7-11dd-bd71-f92a316d2d60
Fixed problem in index() and rindex() NULL pointer returns.
Nicer handling of printing NULL pointers.
New test suite for strings.
git-svn-id: http://picoc.googlecode.com/svn/trunk@353 21eae674-98b7-11dd-bd71-f92a316d2d60
