v0.2.0: Overhauled plugin using less invasive methods that should be less buggy

There are several significant changes in this release:

1. There is no more overriding of important JetBrains classes (this was a hack to get newline type, trailing space, and final newline support to work--more on that below).
2. Support for trim_trailing_whitespace and insert_final_newline is removed for now. It will be re-added in a robust way once this pull request (or something like it) is incorporated, which adds an extension point in IntelliJ itself. A version of the plugin that takes advantage of the change is on the "future" branch.
3. Support for end_of_line is removed indefinitely, as the implementation of this setting caused a lot of problems, and IntelliJ handles newlines pretty intelligently anyway (e.g. it is impossible to mix newline types in a single file).