Adjust width hueristic for Numeric Axis.

Now draws all ticks and takes the longest, rather than speculating
as to which will be the longest.

Added tests for width() and height() on Numeric Axis.

Added some documentation for Custom Formatter.

Close #604.
Add missing semicolons.
Merge branch 'master' into 604-numeric-axis-width
Merge branch 'master' into 604-numeric-axis-width
Switch to using TextMeasurer.
Merge branch 'master' into 604-numeric-axis-width
Adjust calculation to account for negative signs and variable-length formatters.
Merge branch 'master' into 604-numeric-axis-width

Conflicts:
	plottable.d.ts
	plottable.js
	src/utils/formatters/customFormatter.ts
Add in Dispatchers.

Dispatchers are essentially a higher-order proxy for event listeners.
They namespace event registration, so multiple dispatchers can listen
for the same event on the same element.

This is part of the setup for better Interactions in the future.
Rather than create ad-hoc listening structures in each Interaction,
in the future Interactions should use Dispatchers to listen for
events and respond accordingly.

Currently there is only the base Dispatcher and Mouse Dispatcher, but
more will be added in the future.
When there is insufficeint space to fit text, don't write any text at all

This should lead to cleaner failures when there's insufficient space.
Add unit test, commit built files
Merge branch 'master' into add-dispatchers
Merge branch 'master' into 604-numeric-axis-width
Fix IE test failures caused by Time Axis tests choking.

Time Axis tried to set text-anchor to "left", which isn't a valid
value.
using grunt-ts@1.11.6 to use the latest version of typescript
renamed renderer -> plot in css
removed extra line added by accident
Merge pull request #762 from palantir/fix-ie-tests

Fix IE test failures caused by Time Axis tests choking.
cicle-plot => scatter-plot
Merge branch 'master' into typescript-impatient

Conflicts:
	plottable.js
	test/tests.js