Add X-Y-Z slices at dataset center for Slice View default

Change-Id: I8d27f8c103bd607b664f73ece4756f854f06e6b1
Fix compile errors and warnings on Linux

Change-Id: I058d12c2bf7cd7e82ab06815c46609d543b1f728
Modify MultSlice tests for new default view.

Since now we have three slices (X,Y,Z) based on center of the dataset, the
create slice event was removed to simplify the testing results due to
variance in detecting mouse click postions on different machines.

Change-Id: Ie179f3b517150d98f90718119842277d56c69e29
Merge topic '13872_sliceview_default'

f648756 Modify MultSlice tests for new default view.
0f0368d Fix compile errors and warnings on Linux
260d706 Add X-Y-Z slices at dataset center for Slice View default