Fix handling of opacity/alpha channel in pqColorSelectorPropertyWidget.

Properties with 4 component colors now work correctly by presenting
users with a color dialog that allows them to pick the alpha value.

Change-Id: Iba681e399a60a170acc4a69eb2a30c7a296f5dcc
Cleanup view properties panel.

Reorganize properties shown for Chart views by default to make the panel
not be as long by default as they are currently.

Change-Id: I178d622a1cfa723f49400a6f6a14f668342ec85e
Merge topic 'misc_chart_panel_fixes' into next

ac0c3353 Cleanup view properties panel.
1c8c07cb Fix handling of opacity/alpha channel in pqColorSelectorPropertyWidget.