Improved permissions, localization, data format support

This release includes some potentially breaking changes due to an overhaul of the permissions setup, as well as (yet another) rename of the configuration parameters (for future-proof consistency and clarity). Thus it bumps the major version indicator.

In more details, the release:

• Adds appropriate permission levels and groups for accessing special pages. See issue #49
  • Permission levels: rdfio-admin, rdfio-import, rdfio-sparql
  • Groups: rdfioadministrator, rdfiocurator (similar to the smwadministrator and smwcurator).
  • rdfioadministrator gets all permissions (rdfio-admin, rdfio-import, rdfio-sparql)
  • rdfiocurator gets content editing permissions (rdfio-import, rdfio-sparql)
• Updates the i18n config to use json files (see issue #47), and also makes sure to use i18n strings everywhere in the special pages.
  • So, now you can contribute translations for your language, by copying the strings in en.json into your language's file! 👍
• Now supports RDF/XML in the RDF import form (again). See issue #30
• Did some long over-due code clean-up in the wiki title conversion code. See issue #27

Note also the very recently added:

• Support for latest Semantic MediaWiki 2.5 / MediaWiki 1.29 (v.2.4.0)
• Support for blank RDF nodes in import (v.2.3.0)

The vagrant box (automated virtual machine setup) is also updated with RDFIO 3.0.0, providing the absolutely easiest way to try out RDFIO.