Graphite web accepts string input for parameters that should be floats or ints; CarbonAPI does not

[carrieedwards]

Describe the bug
Graphite web appears to allow users to specify strings for functions that that parameters that should be floats or ints. This can be seen in the parameter validation. When the validation functions for floats or ints are called, the values are casted into the float or int data type. CarbonAPI throws an error if a string is passed in for a parameter that is supposed to be a float or int.

For example, the following method would be handled in Graphite web:

scaleToSeconds(testMetric, '5')

But it would throw a 'bad type' error in CarbonAPI.

CarbonAPI's handling of parameters should be updated to match how CarbonAPI does it, so CarbonAPI should allow strings to be passed in for ints and floats.