Updated from Qt Creator commit 1a1ddf1

Commits:
 * 17ce7d4 Replace set[Plain]Text(QString()) with clear()
 * cf8a614 Merge ITextMark and BaseTextMark
 * 9e2512d FakeVim: Remove excess frame from Mapping options page
 * 93304df Always pass Core::Id by value.
 * 6e9b724 Editor: Blockselection rewrite.
 * 84e176e CleanUp usage of QtAlgorithms
 * 98ae1bf Make document model API more consistent with entry vs document
 * 2e37897 FakeVim: Move setting category icon from Core to FakeVim
Python: Removed redundant namespaces
Python: Complete interface implemented