Improve subtitles font rendering

[glaubersm]

Hi
I reported the bad subtitles appearance to Devede NG developer, he said this is a Spumux issue.
rastersoft/devedeng#61

I use dvdauthor 0.7.2 on Arch linux.
Can you improve the subtitles font rendering please? Thanks.

[ldo]

Patches welcome.

[glaubersm]

From me? Sorry, I'm not a software developer.

[glaubersm]

Unreadable subtibles from SVCD created with Devede NG.