adding pluginPath property to qt information

Change-Id: Ib9c2d09c27142de4d19a41afda8ad734e1c22eed
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
add cpp.commonCompilerFlags, flags for all compilation commands

These flags can contain code generation instructions for example.

Change-Id: If430f17c2ded80bb6cb8b4af342d2b6e305ed8ea
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>