Improve cli documentation

- Changes to documentation to make it more concise
- Improve installation steps documentation
- Surface available commands and mostly used options
  
```
$ origami-build-tools
```
Now outputs:

```
Usage: origami-build-tools <command> [<options>]

Commands:
   install  Install system and local dependencies
   build    Build module in current directory
   demo     Build demos into the demos/ directory
   verify   Lint code and verify if module structure follows the Origami specification
   test     Test if Sass silent compilation follows the Origami specification
   docs     Build module documentation into the docs/ directory

Mostly used options include:
   [--watch]                    Re-run every time a file changes
   [--local]                    Build demos locally, and preview them in a browser
   [--updateorigami]            Update origami.json with the latest demo files created
   [--js=<path>]                Main JavaScript file (default: ./src/main.js)
   [--sass=<path>]              Main Sass file (default: ./src/main.scss)
   [--buildJs=<file>]           Compiled JavaScript file (default: main.js)
   [--buildCss=<file>]          Compiled CSS file (default: main.css)
   [--buildFolder=<dir>]        Compiled assets directory (default: ./build/)
   [--scssLintPath=<path>]      Custom scss-lint configuration
   [--jsHintPath=<path>]        Custom JS Hint configuration
   [--editorconfigPath=<path>]  Custom .editorconfig

Full documentation: http://git.io/bBjMNw
```
Cool.

How does that look:

```
Building local and build service demos (config: demos/src/config.json)
WARNING: Deprecated demo config format. Generating the new format...
[
  {
    "template": "demos/src/base.mustache",
    "name": "base"
  },
  {
    "template": "demos/src/skinny.mustache",
    "name": "skinny"
  },
  {
    "template": "demos/src/standard.mustache",
    "name": "standard"
  },
  {
    "template": "demos/src/standard-skinny.mustache",
    "name": "standard-skinny"
  },
  {
    "template": "demos/src/custom-responsive.mustache",
    "name": "custom-responsive"
  }
]
Copy and paste this config into origami.json, or run origami-build-tools
with --updateorigami to update origami.json with the new configuration format
```