Added unittest dependency and fixed small typo.
Merge branch 'master' of https://github.com/DrMarcII/webdriver

Conflicts:
	pubspec.yaml
New WebDriver API.
Introduced _WebDriverBase as a base class for most classes.

Other minor fixes.
Fix typo.
Various cleanup.

Added initial tests.
Minor fixes to command_processor.
Add lots of tests and fix bugs identified by these tests.
Remove unnecessary expectAsync1() calls from tests.
Added tons more tests. Fixes for bugs found by tests.
Fixes in responses to comments.
Fix test name.

Add missing dartdoc to some WebDriver methods.
Uncomment some lines I accidentally left commented out.
Addressed pull request comments.

Rev'ed the version number to 0.7.
Refactored 'ELEMENT' string to _ELEMENT const. Some minor other cleanup.
Merge pull request #1 from DrMarcII/master

WebDriver API rewrite