wireproto: provide accessors for client capabilities...
wireproto: provide accessors for client capabilities
For HTTP, this refactors the existing logic, including the parsing of
the compression engine capability.
For SSH, this adds a ssh-only capability "protocaps" and a command for
informing the server on what the client supports. Since SSH is stateful,
keep track of the capabilities in the server instance.
Differential Revision:
https://phab.mercurial-scm.org/D1944