Reviewed-by: hjk

Discussed-with: hjk

The Parentheses, TextBlockUserData and TextEditDocumentLayout classes
and their member function implementations were spread around the
BaseTextEditor class. Moving them to their own file to make the code a
bit better organized.

Reviewed-by: mae

When copying text editor settings, put incremental search on true.

Reviewed-by: hjk

Also use spin boxes for the number inputs.

Reviewed-by: hjk

Reviewed-by: hjk

Merge-request: 132
Reviewed-by: hjk <qtc-committer@nokia.com>

Merge-request: 132
Reviewed-by: hjk <qtc-committer@nokia.com>

Merge-request: 132
Reviewed-by: hjk <qtc-committer@nokia.com>

Some categories do not have icons yet, unfortunately.