fixes for pandas deprecations and other minor issues

fixed linux and windows for upto 3.11

adding build for python 3.10 and 3.11

builds for linux & windows for python 3.8/3.9

support for list of pathnames in get_ts function

updated to support python 3.7,3.8 and 3.9

fix for issues #25, #26, #27

Fix for offset of WEEK and handling of IR-DAY and DECADE. Updated docs

more fixes for create_new flag tests

fixing tests for create_new flag