Changes from 2.3.0 to 2.3.1

• Support for negative values for BLOSC_TRUNC_PREC filter. Negatives values mean reduce mantissa precision bits, whereas positive values mean keep precision bits.

• Re-add the check for small buffers and a new test (see Blosc/python-blosc2#46).

• Make static a couple of funcs to avoid collisions. This can be useful in case someone tries to compile both C-Blosc and C-Blosc2 in the same name space (however, don't do that unless you know what you are doing; better use dynamic libraries which allow for a much better name space separation).