merge with stable

convert: better grouping of command line flags in help We normally put related command line flags after one another.

convert: help string cleanups

convert: better quoting in help text

convert: show example splice, author, and branch map entries in help Also document that - empty lines are skipped and comment are supported in author map - whitespace is not allowed in branch map entries since we split on it when parsing the file

hgweb: support very simple caching model (issue1845)

tests: extend get-with-headers to support cache testing

tests: fix test output for test-hgweb-no* tests

tests: rename test for better grouping

check-code: fix ternary expression introduced in 1ef9b0b5efec