Added calories conversion

I'm using iPod Nano 6th gen and wanted to convert workouts to .tcx files using your great .xsl. Then I'm uploading them to Endomondo.

One thing I missed is calories - they are not converting in nike+totcx.xsl template. It's a simple conversion using one XSL rule. Tested in Endomondo - they accepted my file and showed me the burned calories.

Please update your .xsl or ask me if you need my help.