User name is schema name if schema is otherwise unspecified.

Minor refactoring to allow for unit test.
Allow = for dump and protobuf options
Clarify name, comment
Test user name defaulting
Typo
merge nathanlws: Better schema defaults

Merge pull request #108 from nathanlws/sql-layer-client-tools/better-schema-defaults
https://github.com/FoundationDB/sql-layer-client-tools/pull/108