Merge patch-1 fix for deprecated preg_split parameter

Merge pull request #1 from mferrara/patch-1

Fix for deprecated use of null as parameter where int is expected

Fix for deprecated "self" in callable

v0.1.5

Update to fix deprecation of using "self" in callables

Fix for deprecated null usage

Fix for deprecated use of null as parameter where int is expected

  DEPRECATED  preg_split(): Passing null to parameter #3 ($limit) of type int is deprecated in vendor/nlp-tools/nlp-tools/src/NlpTools/Tokenizers/WhitespaceTokenizer.php on line 17.