Pymelsec

* moved various functions into utility.py
* add compabitility when reusing result from previous read

* fix typo in tag.py

* set default tag fields as empty string

* remove "Success" from error; now empty string
* update README

* unofficially add SLWORD and ULWORD support
* Mitsubishi doesn't officially support these data types
* update README

* breaking changes
* change case for data type (e.g. sWORD->SWORD, uWORD->UWORD)
* deprecate `def batch_read_{words, bits}`
* add `def batch_read` to handle all data types
* add bool_encode to `def read`
* deprecate `def batch_write_{words, bits}`
* add `def batch_write` to handle all data types
* deprecate `def random_{read, write, write_bits}`
* write bit functions handles int (1) or bool (True)
* add LWORD/ULWORD in case Mitsubishi decides to support them
* update README