Itereate over the hash keys instead.

Change-Id: Ib14bef708b74ed1938bcb985b3a5091aca704391
Reviewed-by: Ulf Hermann <ulf.hermann@theqtcompany.com>
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

and make sure there are not too many of these threads
running at any time. This stops the massive process
startup when loading a project with many UI files, etc.

Task-number: QTCREATORBUG-15795
Change-Id: Icfcddd80d04e36b61ecafbbefe5a1a8b7ea02ec6
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>
Reviewed-by: Ulf Hermann <ulf.hermann@theqtcompany.com>

Avoid conversions when they're not needed.

Change-Id: I7e996bc6e87be4327d75f0d743ff2de38d6ccc32
Reviewed-by: Ulf Hermann <ulf.hermann@theqtcompany.com>

Allow for different extra compilers which may get called to generate
additional code for the code model. The build system is expected to
know what files are generated from which source file and the extra
compilers know how to generate the content of those files, without
touching the build directory. the uic adapter is refactored to be
the first such extra compiler.

The extra compiler is run when an editor for its source document
loses focus, or after a timeout of 1s when the source document has
been changed.

Change-Id: I13c110c61120c812f02639a3684144daf8979b37
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>