Cmake improvements
- Split setup of Boost and NetCDF into usmlBuildSetup.cmake
- Add config directory to CMake module path instead of copying into
  /use/shared/cmake directories.
- Create FindUSML.cmake routine for use my USML applications.
- Allow USML to work with the Boost 1.41 that comes with CentOS.
- Use the progress_timer from Boost 1.41 instead of auto_cpu_timer from 1.57.
- Update install instructions to reflect improvements
  in installation process.