bin collisions in histogram_from_sketch possible

[jamie256]

Summary

If a dataset profile has logged values in a relatively tight range but are large in absolute value, and there are enough bins, the bin edge calculations can hit collisions because of numeric precision on the float values used.

This affects the conversion of the profile to a summary.

[jamie256]

mitigation in place to prevent errors due to bin width collisions, will follow up in next version to support calling a double version of the kll_sketch so we have closer to the expected precision coming from python floats.