fix changed return types
add a test
Merge pull request #46 from devoncarew/devoncarew_fix_types

Fix an issue with changed return types from element measurements
EditSession : change `scrollLeft` / `scrollTop` and their events from `int` -> `num` to support sub-pixel precision

Some platforms, such as Chrome, are starting to support sub-pixel
precision and we may get non-integer values coming up from ace / the
dom.  We were actually calling `toInt()` to coerce these into integers
before but I think its best to let them propagate as numbers and let the
user decide what to do with them.
CHANGELOG : add a note regarding the `int` -> `num` changes
update to ace-builds 06.09.2014

new modes: APPLESCRIPT, DOCKERFILE, VALA
new themes: CLOUD9_DAY, CLOUD9_NIGHT, CLOUD9_NIGHT_LOW_COLOR
mode : add `.vala` -> Mode.VALA default extension mapping
release version 0.4.0+6.9.2014
0.4.1-dev+6.9.2014
disposable : fix type `help` -> `held`
mode_test : update TODO w/ link to a PR fix
remove docgen in favor of dartdocs.org goodness
pure.dart : add a note to the dartdoc that this implementation is not yet ready for use

As the library shows up on `dartdocs.org` some users may otherwise
expect it to work
release version 0.4.1+6.9.2014
0.4.2-dev+6.9.2014