cpp-netlib 0.11.1RC2 (new formula)

Modified from seemingly abandoned PR https://github.com/Homebrew/homebrew/pull/29511
- upgraded to 0.11.1RC2
- added a test
Thanks for your help Mike... That gives me -I/usr/local/Cellar/cpp-netlib/0.11.1RC2/include but I also need -I/usr/local/include so it will find boost. (Same thing with -L#{lib} which doesn't help it find the boost libs.) Is there a way to get /usr/local or can I just hard code that in the test?