1) Place Message Center into the same UI frame as Surveys and About.
2) Center Surveys and About vertically within the displayport.
3) Force Message Center to fill the displayport.
Add slide up/down animation for Message Center.
Merge branch 'dialog_surveys_2' into message_center_ui_2
Merge branch 'dialog_surveys_2' into message_center_ui_2
Update README, CHANGELOG, and bump version.
Merge branch 'message_center_ui_2' into dialog_surveys_2