revset: add a `__nonzero__` to baseset We are about to add a base class for `baseset` with an abstract `__nonzero__` method. So we need this method to be explicitly defined to avoid issues. The built-in list object apparently does not have a `__nonzero__` and relies on `__len__` for this purpose?

revset: drop isinstance(baseset) in spanset.__sub__ As baseset now has a fast __contains___ operator, this `baseset.set()` dance is no longer needed. No regressions are visible in the benchmark.

revset: drop isinstance(baseset) in spanset.__and__ As baseset now has a fast __contains___ operator, this `baseset.set()` dance is no longer needed. No regressions are visible in the benchmark.

revset: drop isinstance(baseset) from baseset.__and__ As baseset now has a fast __contains___ operator, this `baseset.set()` dance is no longer needed. No regressions are visible in the benchmark.

revset: use direct access to __contains__ in spanset.__sub__ Using `x.__contains__(r)` instead of `r in x` does not matter for built-in type (set) but have a positive impact for all other classes. This will let us drop some usage of baseset.set() in future patches. This also probably improves some performance.

revset: use a single return statement in matcher function This makes it easy to insert post processing and debug code on the returned value.

obsolete: replace "nb" notation with "num" (for "number") As requested by Matt Mackall.

shelve: remove unused status variables

gpg: use an abort hint and don't mention --force

gpg: move test of force before status call