CoCoA 5 support

[ThexXTURBOXx]

Please add the following language:

• language name: CoCoA 5
• file extension(s): cocoa5, c5, cpkg5, cocoa5server
• method(s) of commenting text: EOL comments start with either -- or //. Also, multiline comments are supported like this: /* commented text */
• location of sample code: I have modified one of my files to feature every comment type at least once: Buchberger.zip
• software URL: https://cocoa.dima.unige.it/cocoa/