Add setting for espeak '-m' SSML markup support

[muflone]

It would be nice to be able to toggle espeaks SSML support setting (-m added to the command line). Maybe a checkbox in the Advance Settings area?

To see the SSML settings supported by espeak look here:

http://espeak.sourceforge.net/ssml.html

Gespeaker could handle html formated files then too. When this is enabled many html tags are ignored/not spoken.

It would probably be best to have this setting off by default.

Thanks for everything you have done with this little program so far.