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.
Utilise setuptools-git to ensure all versioned files are included in dists
Merge branch 'master' of github.com:collective/collective.recipe.solrinstance into solr-4.5-config-fix

Conflicts:
	collective/recipe/solrinstance/templates4/solrconfig.xml.tmpl
Update changelog.