Fixed wordwrapping of subtitles.

[JontomXire]

I made this change some time ago but I don't think I ever submitted it. I have been using it for years and it works fine except where subtitles are so long that when divided across the maximum number of rows they still go off the edge of the screen. But are still very readable.

[torarin]

As discussed previously (#88), I don't understand why you are changing the preparation code. I don't think the preparation function should change the formatting of a subtitle, merely prepare it for rendering. It would make more sense for wrapping to be done some time prior to calling prepare, so that prepare is given already wrapped text lines for rendering.

[JontomXire]

I am very far from an expert on the OMXPlayer code. As far as I remember I put it here for efficiency. This function is already looping through the lines and calculating line widths from character widths, so it made sense (to me) to do the word wrap here.

Frankly I am not that bothered if you don't take this commit. Since I first started using OMXPlayer I have learnt a lot more about Git and am now quite happy to maintain my own fork including any updates that you are unwilling to take. However this change would benefit others, so I offer it here.

If you can find a better way to implement the same change, then feel free to do so.

[Ruffio]

@popcornmix how about this one?

[Ruffio]

@popcornmix Can this be merged?