Removed large quantities of content from README.

These are more appropriate to the website, in terms of explanation of
SALVE and so forth.
Added examples to compensate for reduced README.

The examples include a zsh manifest, a vim manifest, and a root.manifest
that contains both of them. This demonstrates basic usage of SALVE.
Added a simple "Quick Start Guide."

Demonstrates using SALVE to manage a bashrc, the recommended fork-pull
usage, and a quick description of what SALVE can be used for.
Removed sections about the language specification from README
Added a Changelog to the README
Merge branch 'documentation/simplify-readme' into dev