This reverts commit 2b3a490f7cd45afc294aedad55196b7a5a89813f.

The install_manifest.txt is actually in the top-level binary directory, not the project-specific binary directory.  I get the CMake error 'Cannot find install manifest' if I've added the glew library as a subdirectory in my existing CMake project.

Include description of glew in README.md

Description has been taken from glew.sourceforge.net

Adding conan packaging support