[mythtv] font char width on some osd lines

[Mark Spieth]

Im seeing double width text chars that are overlapping/partially occluded 
with adjacent chars on some osd when interlaced video is shown. it doesnt 
happen when the video is progressive.
example is title text in the timestretch adjust bar. using retro for my 
test.

If someone can give me a hint as to where to start to look for this Ill 
figure out a fix.

Mark Spieth
Digivation Pty Ltd