protocol: add proto to method prototypes

protocol: use new wireproto infrastructure in ssh - add protocol helper - insert wireproto into dispatcher - drop duplicate functions from hgweb implementation

protocol: introduce wireproto.py - add a protocol-independent dispatcher - move most of the basic commands from sshserver to wireproto - dispatch through wireproto first

protocol: move most ssh responses to returns

protocol: add ssh getargs - introduce getargs - make getarg a helper function - update users

discovery: remove duplication for new remote head discovery

discovery: better coding style

discovery: simplify findoutgoing(), the updated_head stuff wasn't used

mq: evaluate --user before invoking editor with -e (issue2289)

Abort: add a hint argument, printed in the next line inside parenthesis discovery was using a custom made message for this purpose push now returns -1 after aborting, instead of 1 previously