Improve message api challenge 1.

[damienmarchal]

Currently we can do

msg_info(this) << "This is a message" 

or

msg_info("ACustomID") << "This is an other message"

Being forced to write the 'this' is ugly so I would like to improve the API to make the following cases possibles

msg_info() << "Héhé"
msg_info(anObject) << "Haha"
msg_info("ACustomID") << "Hihi"

I didn't managed...but maybe you have an idea ?

DM