dir2ogg should not re-convert already converted files

[cwildfoerster]

Hi,

i tried to use dir2ogg to convert my FLAC library to OGG, so i can use my music on my phone more efficiently. My music library is quite large, so the process took a while and after my ssh connection was unfortunately closed, i needed to restart dir2ogg just to notice, it started to re-convert every file it already has converted.

I think this is wrong. I wanted to use dir2ogg as a cronjob to automatically convert all new FLAC files.

[cwildfoerster]

Hi,

i submitted a pull request #3 to fix this issue.