Add ability to add and remove fields from records:

    { book - title }
    { book | pages = 100 }

From these we can derive renaming fields and replacing values:

    { book - title | name = book.title }
    { book - title | title = "Harry Potter" }

There is no syntactic short-cut to batch addition and removal of fields in a single expression.

There is already a convenient syntax for record updates added
in a previous push that lets you do batch updates:

    { book | title <- "Steppenwolf"
           , author <- "Hermann Hesse" }
Bump version number to 0.7.
Enable record pattern matching in let-expressions, and fix a toJS error in which records added a newline that could cause them to be parsed weirdly by JS.
Get rid of FrameRate example which has been replaced by `fps` function.
Fix bug with importing DOM nodes.
Simplify code for occurs check.
Add parsing for record types.
Fix the Open Street Map example.
Remove some unsafe printing.
Minify RTS
* Fix renaming issue with `a1`, `a2`, etc. as described in [issue 75](https://github.com/evancz/Elm/issues/75)

* Switch to using $ instead of _ when depriming variables.

* Bump version number
Ensure that gifs work in collages in all browsers.

Add the `arrows` and `wasd` values to the Keyboard library. Makes it way way easier to deal with directional input.
Add new keyboard signals:

    shift, ctrl, space :: Signal Bool
Fix bug in Automaton.js
Get the touch library working, and bump the version number to 0.7.1.
Add the 0.7.1 RTS which includes the new Keyboard and Touch signals.