pystring

pystring provides many string processing functions, such as split and strip. You can follow the python method to process Lua strings

## support function

* split
* rsplit
* partition
* rpartition
* splitlines
* strip
* lstrip
* rstrip
* join
* startswith
* endswith
* find
* rfind
* count
* shift
* swapcase
* capitalize
* title
* capwords
* islower
* isupper
* isdigit
* ishex
* isalnum
* istilte
* isfloat
* ljust
* rjust
* center
* zfill
* replace
* expandtabs