ENH: Add support for the LPS coordinate system for CLIs

Add a coordinate system flag check, default to ras but support LPS.

Update the displayable nodes that use the WriteCLI method to
use the coordinate system flag.

TODO: IJK coordinate system - See issue #2979

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22311 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Set strings to null after delete

Set strings to null after they've been deleted, trying to
avoid seg faults when debugging

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22312 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: Move the color conversion utility methods

Move the C++ color / Qt color conversion methods out of
Annotations and into qMRMLUtils.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22313 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Fix pan bug in annotation displayable manager

Comparison for valid viewpoint coordinates wasn't properly
checking the first coordinate.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22314 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: Add the ability to access displayable managers.

Added get nth displayable manager to the displayable manager group, and
get displayable managers to the ThreeD view and widget
Useful for debugging displayable managers.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22315 3bd1e089-480b-0410-8dfb-8563597acbee
ENH: Expose module displayable managers to Python

Before this change, you could get at module displayable managers but not
call any of their specific methods in python. This change follows the
pattern of the module logic init file.

To get at the module displayable managers for the first 3D window:
lm = slicer.app.layoutManager()
td = lm.threeDWidget(0)
dms = td.getDisplayableManagers()

The markups fiducial displayable manager was at index 7 in my test:
mfdm = dms.GetItemAsObject(7)
h = mfdm.GetHelper()
from there you can debug the seed widgets

Annotation, Volume Rendering and Tractography displayable managers
are now also accessible from python.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22316 3bd1e089-480b-0410-8dfb-8563597acbee