#33 Patch for WITH_STATIC_LIBRARY option

[Chris LeBlanc]

I'm using Cmake to build on Windows (MSVC) and Linux (gcc). In Linux the defaults appear to build both shared and static libraries. In Windows it appears that you need to enable the option WITH_STATIC_LIBRARY to get a static library. If you enable this option on Linux, you'll get linking errors (undefined symbol log10, pow, etc) from a missing math library.

This small patch adds the existing MATH_LIB to the CGREEN_STATIC_LIBRARY, and works for both Linux (64 bit) and Windows. Tested against revision 553 of Cgreen trunk.

[Thomas Nilefalk]

Added to r557