Makes default capabilities sets minimally consistent for all bindings.

What's done:

1. C# binding
* fix htmlunitwithjs caps
* fix platform for chrome caps

2. java binding:
* add htmlunitwithjs caps

3. javascript binding:
* fix ipad, iphone browser names
* add htmlunit, htmlunitwithjs caps

4. Python binding:
* fix platform for safari caps

5. Ruby binding:
* adds htmlunitwithjs caps
Makes native events on by default for IE.

Fixes issue #4695.