Rewrite the README to describe FRP and RAC in detail
Remove problematic parens from a URL
Fix a few typos and clarify a point
Update login example to reflect the removal of RACMaybe
Make some clarifications based on feedback from @jspahrsummers
Merge the "Examples" section into the other code samples and add detail
Add Getting Started instructions to the README

Completes #13.
Stub Design Guidelines and Framework Overview
"Streams" section
"Signals" section
Fix overview links
Fix anchors?
Bring signals and sequences up a level for readability
Some clarification about signal events
"Sequences" section
"Value types" section
Fix link
"Subscription" section
"Disposables" section
"Subjects" section