CppTools: honor pre-compiled headers in the code-model.

Task-number: QTCREATORBUG-476

Change-Id: I82ed92acdcda551d2c6a9ca221832ac20117a08f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
Qnx: Fix qbs build.

Change-Id: I0779ac1ed42cf1d6815ec278b2a9fb2c6c3bf775
Reviewed-by: Mehdi Fekari <mfekari@blackberry.com>
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
C++: add code-model support for defines-per-editor.

The UI side will come in another commit.

Change-Id: I1038a438587fe4cef70408f7f627d08837fc192d
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>
CppEditor: introduce include hierarchy

Based on type hierarchy.

Added to context menu ('Open Include Hierarchy')
Shortcut(Ctrl+Shift+I)

'Include Hierarchy' contains:
FileName for which 'Include Hierarchy' is done
Includes(which files are included by current file - tree hierarchy)
Included by(which files include current file - tree hierarchy)

It is possible to open/goto each file by clicking on specific item.
Additionally for 'Included by' files it goes to the line where is include
directive for current file.

Change-Id: I549b1ed64e4c9f6955f60d00efb12950a3259f81
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>