On the user-visible side, only the 'Analyze' mode button disappears,
and instead a combobox to switch between different tools in appears
in the Debug mode toolbar.

Internally, that's quite some re-organzition: The centralized
'Analyze mode is busy' flag is gone, allowing us to run e.g.
ClangStaticAnalyzer and MemCheck in parallel.

Analyzer tools and debugger now share the same mechanism to
generate/load/save dock widgets.

Analyzer tools now create and handle their own start/stop button
when appropriate. In general, Analyzer tools can create/handle more
than one run control at a time.

Further consolidation is possible, e.g. RunControl state handling
could be merged into the base ProjectExplorer::RunControl to
avoid the still existing duplication in ~15 instances.

Change-Id: I91e5940ebc4211f98056d507cf2f7b5f8efe7f07
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>