re #1066 after consultation improved image background, aligned text

Code/Mantid/Images/First_use_Background.png

Code/Mantid/Images/First_use_Background_black.pdn

Code/Mantid/Images/First_use_Background_green.pdn

Code/Mantid/Images/First_use_Background_green_beam.pdn

...tid/Images/First_use_Background_green_beam_black_logo.pdn

Code/Mantid/Images/First_use_Background_mantis.pdn

Code/Mantid/Images/First_use_Background_mantis_washout.pdn

Code/Mantid/Images/MantidPlot_Python_Icon_32x32.pdn

Code/Mantid/Images/MantidPlot_Python_Icon_32x32.png

Code/Mantid/Images/images.qrc

Code/Mantid/MantidPlot/src/Mantid/FirstTimeSetup.cpp

Code/Mantid/MantidPlot/src/Mantid/FirstTimeSetup.ui