v2 docs before release

[gadicc]

Review existing README, move relevent stuff to the docs on the website, update existing material.

Installation / upgrades:

• Upgrading from v0
• Changes since v0
• Fresh install

Usage:

• Examples for JS, Blaze, React
• Date and number formatting
• Server side usage (methods/publish, originalHandlebars)
• Integrations (originalHandlebars, autoform, momentjs, etc)
• Security
• Log levels, trouble shooting, error reporting.
• Roadmap

...