Before, there we multiple overview docs:
- guide/overview
- guide/introduction
- guide/dev_guide.mvc
- guide/dev_guide.mvc.understanding_model
- guide/dev_guide.mvc.understanding_view
- guide/concepts

Now we have:
- guide/introduction: High level description of Angular with the key benefits but without code or any concrete concepts
- guide/concepts: explains all important concepts with a simple example and contains deep links to the other parts of the guide.

 All the old information was moved into existing documents or deleted when they were duplicates.

Migrates the Angular project from Rake to Grunt.

Benefits:
- Drops Ruby dependency
- Lowers barrier to entry for contributions from JavaScript ninjas
- Simplifies the Angular project setup and build process
- Adopts industry-standard tools specific to JavaScript projects
- Support building angular.js on Windows platform (really?!? why?!?)

BREAKING CHANGE: Rake is completely replaced by Grunt. Below are the deprecated Rake tasks and their Grunt equivalents:

rake --> grunt
rake package --> grunt package
rake init --> N/A
rake clean --> grunt clean
rake concat_scenario --> grunt build:scenario
rake concat --> grunt build
rake concat_scenario --> grunt build:scenario
rake minify --> grunt minify
rake version --> grunt write:version
rake docs --> grunt docs
rake webserver --> grunt webserver
rake test --> grunt test
rake test:unit --> grunt test:unit
rake test:<jqlite|jquery|modules|e2e> --> grunt test:<jqlite|jquery|modules|end2end|e2e>
rake test[Firefox+Safari] --> grunt test --browsers Firefox,Safari
rake test[Safari] --> grunt test --browsers Safari
rake autotest --> grunt autotest

NOTES:
* For convenience grunt test:e2e starts a webserver for you, while grunt test:end2end doesn't.
  Use grunt test:end2end if you already have the webserver running.
* Removes duplicate entry for Describe.js in the angularScenario section of angularFiles.js
* Updates docs/src/gen-docs.js to use #done intead of the deprecated #end
* Uses grunt-contrib-connect instead of lib/nodeserver (removed)
* Removes nodeserver.sh, travis now uses grunt webserver
* Built and minified files are identical to Rake's output, with the exception of one less
  character for git revisions (using --short) and a couple minor whitespace differences

Closes #199

the previous version is clipped at the top

also contains all kinds of fixes that I had to make in the docs app to
get the tutorial to render correctly