Remove redundant NULL checks before free()/delete
The ISO C and C++ standards guarantee that it's safe to call these
on a NULL pointer, so it's not necessary for the calling code to
also check.
Fixes https://sourceforge.net/p/swig/feature-requests/70/
It is still a bit rough around some edges, particularly with regard to multi-threading and operator overloading, and there are some documentation bits missing, but it should be fine for basic use.
The test-suite should build and run fine with the current versions of DMD, LDC and Tango (at least) on Linux x86_64 and Mac OS X 10.6.
git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12299 626c5289-ae23-0410-ae9c-e8d60b6d4f22
