COMP: Add global option allowing to skip install of CLI shared library

Option is named "SlicerExecutionModel_NO_INSTALL_CLI_SHARED_LIBRARIES", if
not already set, its value will default to "FALSE".

If set to False, it means that CLI shared library will be installed. This
reveals to be particularly useful when generating MacOSX bundle where
library are automatically copied using the fixup mechanism.

See http://www.na-mic.org/Bug/view.php?id=3051