bzr switch does not respect revision argument

[Adrian Wilkins]

There are two cases ;

== When using -b to create a new branch ==

switch command creates a new branch at the HEAD revision of the current branch, not at the stated revision. After switch, working copy is at this HEAD revision.

Correct behaviour : switch should create a branch who's tip revision is that stated in -r, and switch to it

-r should be resolved with respect to the CURRENT branch

== When not using -b to create a new branch ==

switch command does not switch to stated revision of target branch, it switches to the HEAD.

Correct behaviour : switch should rebind to the target branch as normal, and then update the working tree to the revision stated in -r, not the HEAD of the target branch

-r should be resolved with respect to the TARGET branch