Move YCMInternal in internal-modules directory
Improve versioning using git commit

Also bump version to 0.1.0 as it will be the first public release.
InstallBasicPackageFiles: Add [UPPER|LOWER]CASE_FILENAMES options

The generated files can now follow the uppercase or the lowercase
convention.
Use the v3.0.0 tag from CMake git for CMake 3.0.0
FindOrBuildPackage: Add an extra author warning

The author will be notified if a target with the same name of the
package already exists when including the Build file.