CW audio very clicky, fix provided

[jazzkutya]

Hi,

I found the clicking of the cw audio annoyingly clicky, so I tried to fix it and it seems it's OK now.
Here is my commit:
jazzkutya@413d8b6

I hope you find this useful.
Thanks,
hg2eck

[WardCunningham]

I had trouble with clicks in my javascript version. The html5 sound api seems to have lots of options but everything I tried let me down.

https://github.com/WardCunningham/wiki-plugin-morseteacher/blob/master/client/morseteacher.coffee