Idea 12 compatibility, including first implementation of support for external compilation mode.
Updating plugin to use plugin.xml to register extensions for file type provider and framework detector.
Added a new-style framework detector class to detect .proto files and configure the Protocol Buffers facet when detected.
Prompt for facet configuration when the compiler output path is missing.
Setting the plugin version to 0.5.3.
Changed the Resolver for file type elements to start the search for imported files relative to the referring file.