Release 0.6.0

[pwilkins]

• Modified learningresource panel to include multi select.
• Removed export button for empty repositories.
• Added test for StaticAsset.loader.
• Added export functionality for learning resources.
• Added select2-bootstrap-theme bower component.
• Added Select2 to the JS libraries.
• Created ICheckbox React component.
• Made XML preview box for a LearningResource should be read only.
• Pinned all versions.
• Avoided hitting the database for the search page.
• Added field to Vocabulary to define if it can contain multiple terms.
• Incremented xbundle version.
• Added test for ManageTaxonomies.loader.
• Changed vocabularies listing page to match the design.
• Fixed broken links in the footer.
• Removed console.error statement.
• Fixed bug where export checkboxes were not updated in sync with
  export count.
• Fix test failures due to pylint dependency chain.
• Created StatusBox component to hold messages and errors.
• Added shopping cart for export.
• Changed response vocabulary name to match input and avoid key collision.
• Added docker support for running worker or Web process by environment.
• Extended tests for manage_taxonomies.jsx file.
• Added description path to listing page.
• Removed export view which isn't used anymore.
• Refactored code for reloading module into a function.
• Refactored permission check for listing view.
• Updated Haystack to 2.4.0 - Removed automatic index update from deployment.
• Fixed preview link not showing up in list view.
• Grouped REST tests by common endpoint.
• Changed vocabulary term indexing from string to integer.
• Implemented preview link for learning resource panel.
• Added sorting to search results.
• Implemented learning resource panel updating on every panel open.
• Used different haystack index for tests to prevent conflict with web application.

[bdero]

@pwilkins Please add the release notes to RELEASE.rst and make the commit message Release 0.6.0, both by amending the commit. See release 0.5.0, for example.

[pdpinch]

Not for this time, but for the future, the commit message on the RC should probably have a line of introductory text, i.e. release v0.6.0

I was thrown off by it starting with - Modified learningresource panel...