Ensure changing a core part regenerates solr configuration. Fixes #24.
Preparing release 5.1
Back to development: 5.2
Solr 4.5.0 is stricter when parsing 'solrconfig.xml' and will fail to
start due to duplicate <dataDir> nodes in the file: fix that.
Fix configurations for Solr 4.5 which is stricter. We were previously yielding two `dataDir` directives with the default template.
Utilise setuptools-git to ensure all versioned files are included in dists
Update changelog.