Echo, disableLogs, bufferSize, leftChannel, etc. updated.

-. Fixed echo.
-. Added "disableLogs"         - RecordRTC(stream, {
disableLogs: true });
-. You can pass "bufferSize:0" - RecordRTC(stream,
{ bufferSize: 0 });
-. You can set "leftChannel"   - RecordRTC(stream, {
leftChannel: true });