Replace Python core with pure-Vimscript core ("vimcore") (editorconfi…

…g#119)

* Added support for Vimscript core

- Added "vim_core" mode.
- Use the Vimscript core as the default if it is installed and the user
  has not specified a different core.
- Also, for robustness, accept core modes case-insensitively.
- Added VimScript core to documentation

* Copied in editorconfig-core-vimscript

Per @xuhdev in editorconfig/editorconfig#383 (comment)

From cxw42/editorconfig-core-vimscript@4495efd

Removed caching code, which is not yet used, per @xuhdev in
editorconfig#119 (comment)

* Remove support for all cores but vimscript

- Remove the Python core from this plugin
- Remove all plugin code related to modes other than vim_core
- Update the documentation and README accordingly

Note on tests: All tests now pass with `bundle _1.15.4_ exec rake`.
Thanks to
editorconfig#119 (comment)
for the suggestion on how to make this work.

* Add commands to enable/disable plugin

:EditorConfigEnable, :EditorConfigDisable

* Moved plugin tests from tests/ to tests/plugin/

- This makes room for adding core tests.
- Also, renamed and updated plugin_tests submodule

* Added core_tests submodule and scripts

Scripts are modified from cxw42/editorconfig-core-vimscript@5d85d10

Windows-specific files have CRLF line endings; other files have LF
line endings.

* Core tests in Travis; added Appveyor

- Added the core tests to the existing Travis configuration

- Added Appveyor configuration to permit testing on Windows.
  The configuration is modified from
  cxw42/editorconfig-core-vimscript@5d85d10

- Updated the README to include both badges.  For now, they point to
  cxw42/editorconfig-vim; that will need to be updated when this branch
  is merged.

* Updated license and documentation

Also, fixed typo in Appveyor configuration.

Bump version number to 0.3.3

Update version to 0.3.2

Update editorconfig python core subree.

Merge branch 'master' of git://github.com/editorconfig/editorconfig-core-py

Conflicts:
	plugin/editorconfig-core-py/tests

Bump version number to 0.3

Bump version number to 0.2.4

Version 0.2.3

Bump version number to 0.2.2

Bump version number to 0.2.1

Bump version number to 0.2