Dev/ewma 20141017

Note min/max/nonlinear options used only in the following expressions

+        smoothing = 1.0 - pow(norm_noise, s.kSmoothingScaleCurve/20.0);
+        RC = 3.0*(s.kMinSmoothing + smoothing*(s.kMaxSmoothing - s.kMinSmoothing))/100.0;

They aren't something rigorously kosher to use with EWMA.

As per above, seem to found a way to both reduce the user-facing options -and- make it passthrough less noise -and- react faster to actual signal.

Some other crap-o-la in other commits that can be cherried regardless.

@dbaarda please comment on the sanity of this endeavor.

-sh
I think there is no point in having this "expected_noise_10stddev setting.

The whole point of the noise filter is it calculates the noise variance, which assuming gaussian noise by definition means that 1/2/3 stddevs will be 68%/95%/99.7% of the noise. The point of having this noise filter was to automatically learn the noise levels so that you wouldn't need a manual setting for this.