Support Column with float value

[epantera]

Support Column with float value.

eg: Today the following 2nd column is marked as String instead of Number
2014-10-01 22,81
2014-10-02 24,49
2014-10-03 21,66
2014-10-04 17,36
2014-10-05 17,28
2014-10-06 19,52