buildrpm: introduce --withpython for building rpms that includes Python 2.7

buildrpm: introduce --prepare for preparing without actually building rpms

templater: add "diff" template function "diff" allows to embed changes in the target revision into template output, even if the command itself doesn't take "--patch" option Combination of "[committemplate]" configuration and "diff" template function can achieve the feature like issue231 ("option to have diff displayed in commit editor buffer") http://bz.selenic.com/show_bug.cgi?id=231 For example, templating below can be used to add each "diff" output lines "HG: " prefix:: {splitlines(diff) % 'HG: {line}\n'} This patch implements "diff" not as "a template keyword" but as "a template function" to take include/exclude patterns at runtime. It allows to specify target files of command (by -I/-X command line options) and "diff" separately.

locate: add pointer to files command in help

tests: fix breakage from locate deprecation

locate: deprecate in favor of files

formatter: add pickle format This gives convenient Python2 output. Python 3 users will need encoding=bytes.

commands: add hidden -T option for files/manifest/status/tags These commands have generic formatting support but no way to enable it yet. When this feature is more fully developed, this flag will be unhidden.

formatter: add json formatter

cmdutil: add json style to log-like commands Sadly, this can't be done with the normal templater like we do with XML due to JSON's inter-record comma rules.

encoding: add json escaping filter This ends up here because it needs to be somewhat encoding aware.

encoding: handle empty string in toutf8

formatter: make debug style match Python syntax

files: add new command unifying locate and manifest functionality

filelog: parsemeta stops returning unused key list Currently, only the returned meta dictionary is used. An upcoming change will use the returned text offset.