Optional changes for the data-header-line (#465) branch

[dcslagel]

Description:

This branch is a set of optional changes for the data-header-line branch. The changes are based my review comments. In re-reviewing them, they are minor changes with debatable benefit. So I put them on this optional branch. It can be closed or merged to the data-header-line branch. Then data-header-line could be merged.

Test Results:

----------------------------------------------
lasio/__init__.py             13      2    85%
lasio/convert_version.py      20     20     0%
lasio/d1.py                   11     11     0%
lasio/defaults.py             11      0   100%
lasio/examples.py             42     10    76%
lasio/excel.py                88     34    61%
lasio/exceptions.py            6      0   100%
lasio/las.py                 438     60    86%
lasio/las_items.py           199     29    85%
lasio/las_version.py          50     14    72%
lasio/reader.py              436     27    94%
lasio/writer.py              200     10    95%
----------------------------------------------
TOTAL                       1514    217    86%
Coverage XML written to file coverage.xml


----------------------------------------------------- benchmark: 1 tests --------------------------------
Name (time in ms)                 Min         Max      Mean   StdDev    Median      IQR  Outliers     OPS
----------------------------------------------------------------------------------------------------------
test_read_v12_sample_big     938.1881  1,066.0233  986.8813  51.9347  992.5852  72.6016       1;0  1.0133
----------------------------------------------------------------------------------------------------------

--
Let me know if this change could be accepted (or rejected) or
needs some additional changes to be approved and merged.

Thank you,
DC

[kinverarity1]

This looks great thank you!