Remove unused jdmath functions?

[hamogu]

jdmath contains some functions that are not used in marx. Is is worthwhile to remove them to reduce maintenance?
Below is a list of functions as I find them, but a systematic review may reveal more:

• hist.c: None of the histogram functions are used, except in the demo program to demo rebinning

[hamogu]

Interpolation is defined twice, once for floats and once for doubles in finterpo.c and dinterpo.c. Any fixes to one of those files should probably be applied to both. hist.c shows an approach of using the preprocessor to use the same code for two different data types; on the one hand that's less duplication, but it's also harder to read.