Merge: Manpages

~~~sh
$ man nitg
~~~

A dream come true.

More seriously, toolcontext is extended to be able to generate manpages (in a similar way than completion).
Then a bunch of manpages is generated.

The content of the manpages should be improved but this is better than nothing.

Pull-Request: #825
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>

diff --cc src/toolcontext.nit
Simple merge