Created Locale Name/Symbol and Currency Name/Symbol tables

Documenting the locales and currencies that we support is essential
for the Invoice resource. We present this information in a table
because it is really easy for the user to scan for the locale or
currency they need.
Wrote first draft of specification for using Basic Authentication

Some uses of the API will require the use of Basic Authentication,
since it would be impractical to use OAuth (such as in scripts). I
wrote the first draft that explains how we support using Basic Auth,
and what type of authentication method they should use for their
application.