Remove Point class and use dart:math's Point class.

Increment version number and version constraints.

Change tests to reuse WebDriver instance rather than creating new
instance each time.
Remove Point class and use dart:math's Point class.

Increment version number and version constraints.

Change tests to reuse WebDriver instance rather than creating new
instance each time.
Merge branch 'master' of https://github.com/DrMarcII/dart-sync-webdriver
Changes based on review comments.
Merge pull request #2 from DrMarcII/master

Miscellaneous cleanup