Made location optional in ISOCode
Update load.py to read ISO Codes from ethnologue

Fixes #40
load languages from 17th Ed Missing ISO codes

Implements #47
Update load_all_datasets.sh for reading iso/langs

See #40 and #47
Fix bug in rendering LanguageClassification as unicode
Merge pull request #48 from NESCent/read_iso_codes_ethnologue

Updates to reading ISO Codes and languages