suppress warnings in testharnress

added functionality to override normalizer spec

increases the max number of threads

Fix the test error on windows

build wheel from sdist for testing

support pretokenization in BPE mode.

Updated the document

Merge pull request #664 from danieldk/remove-build-path

Strip build directory prefix in the __FILE__ macro

fixed python module to check the id range.

udpate clang build rule.