Support multiple languages

[DougManuel]

Provide support for multiple languages. Currently, there is support for English and French.

Proposal to:

• have English as a default language for documentation. This means that tables, variables, measures, etc. would include only an English description in the primary table.
  - French descriptions would be moved to a separate language table.
  - Other languages would be added to the language table.
• The language table would have multiple language descriptions for each element in the ODM (tables, variables, measures, etc.).
• We, therefore, require an unique identifier for each element in the ODM.

[DougManuel]

See issue #181 for a proposal for unique id.

[DougManuel]

Sorry, this is a repeat of issue #177. I'll close this issue.