Merging default configuration with configuration in custom file

[artemy-osipov]

When Database-Rider configured via custom file, then missing parameters will be resolved to default java values, not to default values specified in documentation.
e.g. with this dbunit.yml

properties:
  qualifiedTableNames: true
  caseSensitiveTableNames: true
  escapePattern: "`?`"

missing parameter cacheConnection will be resolved to false

[coveralls]

Coverage increased (+0.09%) to 77.48% when pulling 85189ac on artemy-osipov:dbunit-config into 94d4f84 on database-rider:master.

[rmpestano]

Thank you very much @artemy-osipov, I'll review as soon as possible and release a new version.

Happy new year!

[rmpestano]

Thank you again for your great work @artemy-osipov!