Fix commit date (issue1193) The None check in workingctx prevents calling util.makedate when date is not explicitly given.

convert: hg sink commits without working dir

convert: reintegrate file retrieval code in sinks It simplifies the sink interface and all the sinks to handle files data as they want.

context: add memctx for memory commits

merge with crew

coal: remove double template entry

localrepo: interpret ctx.filectx() exception as a missing file

localrepo: do not expose workingctx options These are implementation details and probably of no use to client code.

localrepo: extract _commitctx() from commit() _commitctx() takes a single changectx like argument. It gives way to commits from memory only.

context: let workingctx.date(), .user() and description() be overriden