This is a copy of Source Sans Pro by Paul Hunt, modified as a helper for
path tests. The glyphs have the following properties:

/A base is slightly below the baseline
/B stem is not quite vertical
/C has colinear points on top right terminal
/D has a small path in the bottom left of the counter
/x is not quite aligned to the x height
/E has an erroneous ink trap which should be flagged
/F has an acceptable ink trap which should not be flagged
