fix(ngShow): Add/remove ng-hide class instead of ng-show class

Closes #521
chore(style): code cleanup

fix CS only specify types where strictly necessary
to ease readability.

Closes #522
chore(style): code cleanup
refactor(http): remove a now useless workaround

dartbug.com/13051 has been fixed.
see https://code.google.com/p/dart/issues/detail?id=13051 for details.

Closes #523
feat(ngModel): Treat the values of number and range inputs as numbers

Add a InputNumberLikeDirective that binds the model as a numeric
value, so that it can be bound to num types on scopes. Select the
directive for number and range input types.

Closes #527
test(NgForm): Regression test for #459.

Closes #459
Closes #538
chore(cleanup_todo): Clean-up the TODO sample.
chore(comments): Terminate comment with period.

Closes #539
fix(package.json): add repo, licenses and switch to devDependencies

Fixes #544.
Closes #545