Issue a warning if "-r ." is used with two working directory parents.
Rationale for not aborting instead:
The first parent is usually more important as it is the local branch
during a merge and commands like 'hg diff' and 'hg diff -r.' behave still
identically (except for the warning of course).
Added a test for log -r. with one and two parents.
d40cc5aacc31ed673d9b5b24f98bee78c283062c 0.4f
1c590d34bf61e2ea12c71738e5a746cd74586157 0.4e
7eca4cfa8aad5fce9a04f7d8acadcd0452e2f34e 0.4d
b4d0c3786ad3e47beacf8412157326a32b6d25a4 0.4c
f40273b0ad7b3a6d3012fd37736d0611f41ecf54 0.5
0a28dfe59f8fab54a5118c5be4f40da34a53cdb7 0.5b
12e0fdbc57a0be78f0e817fd1d170a3615cd35da 0.6
4ccf3de52989b14c3d84e1097f59e39a992e00bd 0.6b
eac9c8efcd9bd8244e72fb6821f769f450457a32 0.6c
979c049974485125e1f9357f6bbe9c1b548a64c3 0.7
3a56574f329a368d645853e0f9e09472aee62349 0.8
6a03cff2b0f5d30281e6addefe96b993582f2eac 0.8.1
35fb62a3a673d5322f6274a44ba6456e5e4b3b37 0.9
2be3001847cb18a23c403439d9e7d0ace30804e9 0.9.1
36a957364b1b89c150f2d0e60a99befe0ee08bd3 0.9.2
27230c29bfec36d5540fbe1c976810aefecfd1d2 0.9.3