QmlDesigner: crash fix

prefixNames containing white spaces did crash.
This was lost during refactoring.
Instead of calling toLower one the string
we call toLower only on the first char.
This creates camel case ids.

Change-Id: I1093d12258e87d4f56ceef67a553d844afdfd376
Reviewed-by: Marco Bubke <marco.bubke@digia.com>
QmlDesigner: Fix warning in ImportManager

Change-Id: I3c392ad333b9a7720495073fb8549996c6f1842d
Reviewed-by: Marco Bubke <marco.bubke@digia.com>