Tighten ratom version and move libxml-ruby to runtime list.
Merge branch 'next'

* next:
  Remove Server#version_components from the docs.
  Restrict provenance functionality to correct server versions.
  Document the Server::Version class.
  Use the comparable version class internally.
  Implement a comparable version class.
  Can now toggle provenance generation on and off.
  Add provenance capture and retrieval functionality.
  Fix error in exception caused by chunked response.
  run-workflow: Fix baclava output option.
  Setup rubygems and bundler in the main require file.
  Drop support for ruby 1.8.7.
  Add ruby 1.8.7 back into the travis config.
  Refactor out rexml and nokogiri xml support.
  Add travis badge and update ruby testing info.
  Update note about SemVer in readme.

Conflicts:
	t2-server.gemspec
Align baclava output method names with the prov ones.

New names are better. Old versions are deprecated.
Bump the year in the main Licence file.
Add provenance information to the ReadMe.
Update changelog.
Add ruby 2.1.0, remove ruby 1.9.2 from the travis build.
Adjust version table in the ReadMe.
Use SVG version of Travis badge in the ReadMe.
Merge branch 'master' into next

* master:
  Use SVG version of Travis badge in the ReadMe.
  Adjust version table in the ReadMe.
  Add ruby 2.1.0, remove ruby 1.9.2 from the travis build.
  Update changelog.
  Add provenance information to the ReadMe.
  Bump the year in the main Licence file.
  Align baclava output method names with the prov ones.
  Tighten ratom version and move libxml-ruby to runtime list.
Use SVG version of gem badge in the readme.
Merge branch 'master' into next

* master:
  Use SVG version of gem badge in the readme.