Fix tests for validating lasio json file reading

[dcslagel]

Resolves #43

Fix tests for reading lasio and wellio json files

The tests run with npm run test-las2json are updated as follows:

• to match current test file names
• to add specific wellio-json tests
• to test that null values are read successfully

Test restults

npm run test-read-lasio-json

> wellio@0.1.7 test-read-lasio-json /usr/local/devel/Apps/node-apps/wellio.js
> tape dist/test/read_las_json/test_*.js

TAP version 13
# readLasioJson: test_read_sample_2.0.json
ok 1 should not throw
ok 2 Sample json: LAS is version 2
# readLasioJson: test_read_lasio_sample_2.0_with_empty_headers.json
ok 3 should not throw
ok 4 Sample json, empty headers: 'VERS' key is not in the Version section
# readLasioJson: test_read_lasio_sample_2.0_pretty.json
ok 5 should not throw
ok 6 Sample pretty json: LAS is version 2
# readLasioJson: test_read_lasio_sample_2.0_null.json
ok 7 should not throw
ok 8 Sample json: LAS is version 2
ok 9 Sample json: LAS null value in CURVES.ILD[1] is null
# readWellioJson: test_read_wellio_sample_2.0.json
ok 10 should not throw
ok 11 Sample Wellio json: LAS is version 2

1..11
# tests 11
# pass  11

# ok

Let me know if this needs some additional changes to get approval for merging.

Thank you!,

DC