Created R code to implement multilateration algorithm from the Wikipedia page.  Current limitations:
- Requires 5+ mics, not 4 (might be able to work around that soon..)
- If first 2 mics record exactly the same timing, get NaN results.  Will have to look into but unlikely to affect us for our scenario
Merge pull request #1 from pataelmo/multilateration-code

Created R code to implement multilateration algorithm from the Wikipedia...