Port Version Control Lesson to Mercurial

Please edit the block below to claim a section for translating.

- [x] novice/hg/00-intro.md (@douglatornell): ready for review
- [x] novice/hg/01-backup.md (@douglatornell): ready for review
- [x] novice/hg/02-collab.md ( @seanfarley ): ready for review
- [x] novice/hg/03-conflict.md ( @jordigh ): ready for review

Rendered version of lesson is available for review at http://eos.ubc.ca/~dlatorne/swc/novice/hg/

Items arising from reviews:

- [x] Address @jdcorless comments re: `hg revert` and *.orig files in 01-backup.md ( @douglatornell )
- [ ] Resolve presentation of GUI merge tool(s) and file annotation of 03-conflict.md
- [x] Prune size of SVG images in 03-conflict.md
- [x] Delete unused git image files
- [ ] Add Mercurial installation instructions to `_includes/setup.html`
- [ ] Add check for `kdiff3` to `setup/swc-installation-test-2.py`
- [ ] Add link to explanation of how binary file changes are handled to end of `03-conflict.html`

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@douglatornell's original comment:

Based on conversations with @gvwilson at PyCon 2014 I have started to create a port on the version control lesson material that is based on Mercurial.

This is presently work-in-progress and *not* ready to be merged, however, reviews and comments are welcome.

I started with a copy of the Git lesson files so that diffs in the text content are easily accessible for review.