Add tutorials for ccp

[core-man]

https://blog.seisman.info/ccp-install/

[seisman]

Although ccp is very popular, it requires very old GMT versions (maybe GMT 4.5.5). I'm not sure if we should document it.

[core-man]

Although ccp is very popular, it requires very old GMT versions (maybe GMT 4.5.5). I'm not sure if we should document it.

Yes, let's make ccp as the last one on the todo list.