generate should have a '-pedantic' option

[atuleu]

Such option :

• be disabled by default
• would turn any warning into error
• would turn any undocumented entity found into error
• display a nicely reported error with the source file and line number to stderr for each errors
• if an error happen, cldoc should return with a non zero status

This would allow an easy integration with Makefile and IDEs when developper are producing code and documentation.