ENH: Update CTK (includes PythonQt crash fix, DICOM browser enhancement)

Fixes Issue 0004045 (py_StandaloneEditorWidgetTest crashes on exit in PythonQt)
Fixes Issue 0003792 (unable to remove one series of an exam in the dicom menu)

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commit cbf890f8eda122b8dca8e67d2bf75e85640ab297
Author: Max Smolens <max.smolens@kitware.com>
Date:   Tue Sep 15 15:45:30 2015 -0400

Fix PythonQtSignalReceiver crash during cleanup

This commit fixes a crash during PythonQt::cleanup(). While destroying the
PythonQtPrivate instance, any remaining PythonQtSignalReceivers that are kept
alive only by their parent object will be destroyed. The crash occurs when
PythonQtSignalReceiver's destructor calls back into
PythonQtPrivate::removeSignalEmitter() when the PythonQtPrivate instance is
mostly destroyed.

Includes test case that crashes without the fix.
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commit ea653d2cfc5be6dc846a5a54f75543af7dfd4445
Author: Nicole Aucoin <nicole@bwh.harvard.edu>
Date:   Mon Aug 3 18:51:07 2015 -0400

ENH: add ability to delete individual series, studies, patients

Add to the browser Remove button the information that it will
delete all selected series, studies, patients.

Add support for right click custom context menus in the
patient, study, series tables. Translate the local points
to global ones in terms of the table view and signal
right clicked with the global position so that the browser
can position the context menu appropriately.

Add the context menu to the DICOM browser to allow
deleting at just one level, with number of items
selected information, and a confirmation message box with descriptive
information that can be set to not be shown again.

Added a test for the DICOM browser, with the ability
to open it in interactive mode to test the right clicks.

Add query wrappers for the DICOM database to get the patient name
as well as descriptions for series and study. They will return empty
strings on failure.
Use the new queries to give more meaningful information on the right
click pop up menu in the DICOM browser.
Added a test for the new DICOM database accessors.

Slicer bug:
http://www.na-mic.org/Bug/view.php?id=3792

When Slicer makes a custom DICOM browser, it moves the table views
directly into the new window, extracting them from the DICOM
table.
With this change, the table view takes care of mapping the point to
global, the table manager propagates the signal as a table specific
XRightClicked signal, and the browser responds to it with a table
specific context menu.

Slicer Issue 0003792
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From: Max Smolens <max.smolens@kitware.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24554 3bd1e089-480b-0410-8dfb-8563597acbee