Add Valgrind build to Travis-CI configuration
Quick test to see if Valgrind is really running
Suckier way of valgrind testing, just for Travis-CI!

valgrind testing can now be enabled with --with-valgrind on the command line,
because Travis-CI seems to suck at doing things the other way.
Fix String leaks by implementing destructor (oops)

Derp
Merge pull request #7 from caitp/issue-7

Add Valgrind runs to Travis-CI