Added:
- Class AMAboutDialog ~ A dialog class to display the required build and
legal information in a modal dialog
- class AMBuildInfoWidget ~ A widget class for displaying the
information about a passed build
- AMDatamanAppController::onShowAboutPage() ~ handles selecting of
QAction "About..." in the Help menu

Altered:
- AMDatamanAppController::startupInstallActions() ~ Adds an action to
display the About page, and adds it to the help menu.
Merge branch 'Issue719'