added \r for progress counting in churn extension

update the branch cache at the end of addchangegroup This should avoid a bad performance problem when the branch cache is not up-to-date, and hgweb can't write an updated version because it lacks permissions.

qpop/qrefresh: update self.applied before calling strip This will be important for the next patch, which may end up using this variable during an addchangegroup caused by strip.

hg import: write the dirstate after every commit This allows the transaction system to backup the correct file, so that a future rollback can do the right thing. This should fix issue963.

localrepo._tag: add a seek before writing the new tag Some systems require a seek (or flush) between read and write operations on the same file object. This should fix issue838.

convert: use 'unknown' and '0 0' if commit author or date weren't specified Closes issue873.