refactor env settings for template tests

Split cssText from iframe tests cfg into baseCssText and
additionalCssText. Thanks to this, one may just add a bunch of overriden /
new css properties for a specific test, instead of having to copy-paste
everything.

Base css text, which could be shared by TemplateTestCase and page engine's
IframeTestCase, was moved to TestCase (to have a single source of it
without creating new dependencies / intermediary classes).

Close #586. Close #616.
fix #620 remove @-ms-keyframes

@-ms-keyframes doesn't make sense. It's not supported by any IE version.
feat #618 Bindable disabled attribute

This commit introduces the possibility to bind the disabled attribute of all input-based html widgets as well as the select html widget.

Close #618
fix #622 aria.DomEvent not disposed in some cases
fix #623 Adding support to content when generating HtmlTemplate files

Now is possible to pass a specific content to the method in order to have it inside the template generated.
fix #624 Configurable url generated by page engine
feat #615 Bower manifest

Close #615