Too much for one commit, but inseparable at this point.  Includes: localizing shared constants to shared/i18n, shortening names, decreasing non-debug output, closing file pointers when done, indenting changes, removing API keys from public code, and being explicit about language code formats.
Fix #1138 (move data files to internal data directory), fixed a copule of small bugs.
Validating languages, making internal storage for cache_subtitles use IETF standard, and django to use its own standard.
More refactoring, variable renaming, cleaning--and a few key changes to make use of lang_code (ietf vs django) more obvious and consistent
Merge branch 'release-0.11.1' of github.com:learningequality/ka-lite into lang_code_consistency
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into lang_code_consistency
Fixing bug in branch code and in languagepackdownload code.
removing duplicate language pack defs
just because a srts exist doesn't mean a language pack is available for download.
Merge branch 'release-0.11.1' of github.com:learningequality/ka-lite into lang_code_consistency
removing my old friend
compress language packs--srts are text
Merge branch 'release-0.11.1' of github.com:learningequality/ka-lite into lang_code_consistency
fixing bug in dictionary storage and cross-data validation code
updates based on code review to eliminate loads(read()), tidy up docstrings, and be a bit more informative to the user with output.
test your code before submitting, Ben\!
Merge pull request #1140 from bcipolli/lang_code_consistency

Cleanup of i18n command code to make use of lang_code consistent