fix #493 dispose resources providers

When unloading a class, resources providers instances created at load were not disposed.
fix #495 skip resources providers at template unload

When unloading a template, its resources are also unloaded. When resources are coming from a provider, an error was raised.
The fix consists in skipping those types of resources.
Issue #470 Multiselect disabled Item label remains selectable.

Close #470
fix #496 Error when loading missing localized resources

The url map generated by the build was causing an error in the resources locale fallback mechanism.
feat #486 enhancements in DomElementWrapper

1. Added support for WAI ARIA (`aria-*`) attributes in `getAttribute`
2. Added support for custom `data-*` attributes in `getAttribute`
(previously they could have been retrieved only with `getData`)
3. Added support for expandos with multiple dashes (`data-foo-bar`) in
`getData`/`getAttribute`
4. Added `setAttribute`

Close #486
doc Improve README
fix #424 Ctrl+click opening new tab in @aria:List in IE7

When Ctrl+clicking an option in List widget in IE7, new tab was opened due
to the fact that options are anchors under the hood.

Close #492.
feat #471 Easy loading of templates in iframe

Provide a simple and reliable interface to load and test a template inside an iframe.
This also attempts at deprecating the usage of iframeLoaderOs, see #435

Close #471
feat #489 double slider widget

Add a DoubleSlider widget to the touch widget library. This widget has two
independently movale thumbs.

Close #489
fix #501 Add id in the correct bean for template load

Close #501