convert: refactor sink initialisation, to remove hardcoding of hg
We also introduce options to explicitly set the source and destination
repository types.
Improve testing of corner cases a little.
changeset: 0:9426b370c206
tag: tip
user: My Name <myname@example.com>
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
changeset: 1:4997f15a1b24
tag: tip
user: foo@bar.com
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
changeset: 2:72b8012b424e
tag: tip
user: foobar <foo@bar.com>
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
changeset: 3:35ff3067bedd
tag: tip
user: foo@bar.com
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
transaction abort!
rollback completed
abort: Please specify a username.
No username found, using user@host instead