peer: introduce peer methods to prepare for peer classes This introduces a peer method into all repository classes, which currently simply returns self. It also changes hg.repository so it now raises an exception if the supplied paths does not resolve to a localrepo or descendant. Finally, all call sites are changed to use the peer and local methods as appropriate, where peer is used whenever the code is dealing with a remote repository (even if it's on local disk).

Greg Ward, author of the original bfiles extension
Na'Tosha Bard of Unity Technologies
Fog Creek Software
Special thanks to the University of Toronto and the UCOSP program