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