minirst: modified minirst to also recognize empty comments. The modifies minirst to also handle empty comments. An empty comment is a block with a single line containing two dots.

merge with stable

posix: remove is-comparison between integers Comparing integers by identity relies on a CPython implementation detail of caching integers between -5 and 256.[1] [1] <http://docs.python.org/c-api/int.html#PyInt_FromLong>

httprepo: remove is-comparison with string literal An identity check between a variable and a string literal was added to the pushkey implementation in 6bd9778ae749. While CPython will normally intern strings and thus make the test safe, value identity is what should be used here.