Heap space for razor

The heap space was previously too low,
causing intermittent issues. This changes
the default to 1024MB. The rest of the
options are copied from the standard
Torquebox packages.

Fixes https://tickets.puppetlabs.com/browse/RAZOR-331
Update README.md
Case-insensitive uniqueness

When the user tried to create the same entity twice but with different
case-sensitivities, the server would reach an infinite loop or allow both
entities to exist in the case of Tag. This fix converges those to more
standard behavior by universally rejecting the request to create the entity
twice. The fitting error message will be: "...already exists, and the name
fields do not match".

Fixes https://tickets.puppetlabs.com/browse/RAZOR-313
`create-tag` should be idempotent

Running multiple identical `create-tag` statements
was yielding a "Sequel::ValidationFailed - name is already taken"
error from Sequel instead of PSQL's "UniqueConstraintViolation".
This rectifies that by fielding both exceptions during import.

Fixes https://tickets.puppetlabs.com/browse/RAZOR-274