Version 0.31 (18 May 2023)

• Many improvements to code style and formatting, and the documentation

• #555 - Fix problem when writing with changed data (different number of depths)

• #554 / #556 - Enable DLM (delimiter) TAB

• #552 - Remove or replace cchardet with chardet

• #530 - Detect hyphens in data section and adjust regexp_subs as needed

• #527 - Remove deprecated functions from las.py: add_curve_raw(), add_curve(), and to_json_old()

• Fix #322 - provide a way to consistently retrieve header items which may
  or may not be present in the header:

  If you try ordinary item-style access,
  as is normal in Python, a KeyError exception will be raised if it is missing:

  >>> permit = las.well['PRMT']
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "c:\devapps\kinverarity\projects\lasio\lasio\las_items.py", line 313, in __getitem__
      raise KeyError("%s not in %s" % (key, self.keys()))
  KeyError: "PRMT not in ['STRT', 'STOP', 'STEP', 'NULL', 'COMP', 'WELL', 'FLD', 'LOC', 'PROV', 'SRVC', 'DATE', 'UWI']"

  A better pattern is to use the lasio.SectionItems.get method, which
  allows you to specify a default value in the case of it missing:

  >>> permit = las.well.get('PRMT', 'unknown')
  >>> permit
  HeaderItem(mnemonic="PRMT", unit="", value="unknown", descr="")

  You can use the add=True keyword argument if you would like this
  header item to be added, as well as returned:

  >>> permit = las.well.get('PRMT', 'unknown', add=True)
  >>> las.well
  [HeaderItem(mnemonic="STRT", unit="M", value="0.05", descr="FIRST INDEX VALUE"),
  HeaderItem(mnemonic="STOP", unit="M", value="136.6", descr="LAST INDEX VALUE"),
  HeaderItem(mnemonic="STEP", unit="M", value="0.05", descr="STEP"),
  HeaderItem(mnemonic="NULL", unit="", value="-99999", descr="NULL VALUE"),
  HeaderItem(mnemonic="COMP", unit="", value="", descr="COMP"),
  HeaderItem(mnemonic="WELL", unit="", value="Scorpio E1", descr="WELL"),
  HeaderItem(mnemonic="FLD", unit="", value="", descr=""),
  HeaderItem(mnemonic="LOC", unit="", value="Mt Eba", descr="LOC"),
  HeaderItem(mnemonic="SRVC", unit="", value="", descr=""),
  HeaderItem(mnemonic="CTRY", unit="", value="", descr=""),
  HeaderItem(mnemonic="STAT", unit="", value="SA", descr="STAT"),
  HeaderItem(mnemonic="CNTY", unit="", value="", descr=""),
  HeaderItem(mnemonic="DATE", unit="", value="15/03/2015", descr="DATE"),
  HeaderItem(mnemonic="UWI", unit="", value="6038-187", descr="WUNT"),
  HeaderItem(mnemonic="PRMT", unit="", value="unknown", descr="")]