update_version 0.5.4

[Marcin Kasperski]

Small new release of mercurial_update_version (auto-updating
version numbers on tagging):

- supports updating version numbers in javascript files
  (package.json + VERSION constants in *version.jsx?, exact
  rules may change depending on feedback)

- bugfix: module happened to add additional newline after
  updated version number

See https://bitbucket.org/Mekk/mercurial-update_version
for detailed description and installation instructions.