topic: rename the internal topic option we'll use it more widely so I give it a more generic name. It is an internal option so not wories regarding compatibility.

prev: extract the code computing the destination This make the handling of the result simpler. The test agree as one return code is fixed.

prev: issue a proper error when reaching repository root (and adds the associated test)

prev: stop creating a repository at the root of 'test-repo.t' We run the test in a subdirectory now, this usually avoid various kind of future issue.

prev: extract the function performing the update That code is fairly independant so let us isolate it to simplify the rest of the code.

prev: simplify the bookmark preserving logic We can use 'None' as a special value and have a simpler code.

prev: rename 'p' to 'target' This makes the code clearer.

topics: check for topic on commit before a user enters message We have a enforce-topic cofig which can forbid user to commit without a topic on it. We used to check topic on a commit after the user enters message, but we should fail early.

packaging: update readme I forgot again.

topics: add a new flag --age which will show last touched time for topics This adds a new flag `--age` to `hg topic` command which will show topics sorted by their last touched time and will also show the last touched time for them. This patch also adds a simple test to make sure the flag does not breaks by future changes. Adding more tests showing output like "3 hours ago", "2 minutes ago" etc will change as the code takes time.time() into account which will increase with time, and hence the output will change, so we need some static output like a date.