Fix compatibility with thresholds by epuidokas 

No more holes is the curve when there is not the amount of points in top and bottom curved line.

Flot is already doing it by itself

Prevent calculateCurvePoints from being called twice when filling & drawing line

- removed require.js stuff
- moved options from line: {} back to curvedLine: {}
- resolved a bug with the fit option
- updated examples

Define fill

Although fill was used to determine the fill of the curved lines, it wasn't defined.

Now let flot do the hard work. So all lines options are supported (date axis, shadow, gradient fill, ...)

Small bug fixes
- fill opacity always defaulted to 0
- check of Array.map

added saddle detection which should result in nicer curves and hopefully does not lead to new problems

however to detect the need of a conversion only the first entry in the data array is checked
and the conversion is not really efficient.

Add fill and fillColor options