wiasane: Updated default scanner resolutions to include 75 dpi

Source of default resolutions for WIA flatbed drivers:
http://msdn.microsoft.com/en-us/library/windows/hardware/ff551499.aspx
coisane: Updated detection of supported resolutions

The quantil-based approach did not work in case more than 12 values
below the minimum-value were generated. The new approach uses a
default list of supported solutions and checks that against the
range constraint. Also the minimum and maximum value are always
added to the list of supported resolutions.