Change-Id: I8b73d583be1ee7183f4074bce49d5390e38631a2

rename BastTextEditor->BaseTextEditorWidget, BaseTextEditorEditable->BaseTextEditor
rename BaseTextEditor{,Widget} subclasses
rename editableInterface->editorInterface
rename createEditableInterface->createEditor
minor cleanups after renamings

Task-number: QTCREATORBUG-2674

Reviewed-by: hjk

The C++ hover handler should just iterate over the list of candidates, since
it was created by the element evaluator considering all possible name qualifications
and in the right order.

Reviewed-by: kh1

This is basically for consistency with the docs and with the html
extraction mechanism.

Reviewed-by: Roberto Raggi

Also some less significant improvements.

Reviewed-by: Robert Loehning

Hierarchy information removed from tooltips now.

To catch cases of invalid code like this:
struct A : B {};
struct B : A {};

Reviewed-by: Roberto Raggi

The old integration option is now used to switch to extended descriptions.

We need to add the fully qualified name to the case statements.

Reviewed-by: Roberto Raggi

To conform with recent changes that affected LookupContext::fullyQualifiedName.

Task-number: QTCREATORBUG-1169

Also removed TokenUnderCursor as it's functionality is in the token cache.

Reviewed-by: ckamm

 - lessens open file handles
 - improves help plugin startup further

Task-number: QTCREATORBUG-337
Reviewed-by: ck

This reverts commit c2393df0.