Easy Dialogs and Status Bar

Adds convenience methods to hiero.ui for presenting dialogs (without needing to know the PySide) and setting messages in the Main window's statusbar at the bottom.

Each dialog info/warning/error also logs out at the appropriate log level.

The Mainwindow has a Status bar which is not used by the main application (at time of writing)

You can hijack the Status Bar to display messages, or even show custom PySide widgets such as ProgressBars or Buttons.

(See QStatusBar methods for more details: http://srinikom.github.io/pyside-docs/PySide/QtGui/QStatusBar.html)

hiero.ui methods added by messaging.py (see their help for usage)

hiero.ui.statusBar - returns an instance to the Main Windows Status Bar object.
hiero.ui.showInfo - presents an Info style Dialog box
hiero.ui.showWarning - presents a Warning style Dialog box
hiero.ui.showError - presents an Error style Dialog box
hiero.ui.setStatusMessage = setStatusMessage
hiero.ui.statusMessage = statusMessage
hiero.ui.clearStatusMessage = clearStatusMessage
hiero.ui.toggleStatusBar = toggleStatusBar