Fix #101, install includes to simbody subfolder

Install header files to simbody subfolder to prevent mixing
with other system header files.
Add uninstall target (fix #104)

Adds an uninstall target, so that 'make uninstall' will remove
all installed files, provided that the build folder is retained.
It will not remove any folders that were created during
installation.
Install to include for Win32 sandbox instead of include/simbody
Install cmake config file to different location on Win32

See http://www.cmake.org/cmake/help/git-master/command/find_package.html
for a list of valid install locations.
Merge pull request #107 from scpeters/cmake_install_win32

Install cmake config file to different location on Win32.
Fix uninstall script to handle spaces in file names

Fixed a few cmake syntax problems and added quotation marks
to remove command to handle spaces in file names.
Merge pull request #106 from scpeters/issue_104_uninstall

Add uninstall target (fix #104). Works for files but leaves empty directories.