Deprecate legacy display panel for the Text Source

Change-Id: Iba99bf3caaca50519de6867768da92b5004b168c
Reworked Text Source display panel

Change-Id: I8100cab47ec1ca7aef082265c9d9e99d2bd09c30
Renamed pqTextWindowLocationWidget to pqTextLocationWidget

Change-Id: Iec86a4c3b7043ace4d2b0aa1b575951ee3f12940
Use new display panel for spreadsheet view

Change-Id: I3d4911065c0103798f16b02483bf8c7aa09b247e
Removed legacy display panel widgets

Change-Id: I055cf6f44e3607c40b62915a15bbf1843a2c592a
Changes in FontPropertyWidget and TextLocationWidget

FontPropertyWidget: Added opacity spinbox to control font opacity.
TextLocationWidget: Changed listening from the groupbox clicked()
signal to toggled() signal so that QtTesting tests can simply use
set_boolean command on the groupbox.

Change-Id: Ib7a45875e60d9f70f8a7d4e6f7318750c485e6a8
FIX: Fixed test using the new TextLocationWidget

QtTesting currently cannot record the event of activating a toolbutton to bring
up the associated popup menu. To work around this issue, just add a line before
the QtTesting recorded line to activate the toolbutton.

Change-Id: I14d17187755a9b0595b173e4fc50d8313dd45899