resolve #4 add warnings to HikariConfig.validate() to inform user of misconfigurations, drop back to default values.
Clarify warning message.
Improve pool fill / maintenance strategy subtly.
Fixes and tests for property file-based configuration.
Merge branch 'dev'

* dev:
  Fixes and tests for property file-based configuration.
  Improve pool fill / maintenance strategy subtly.
  Clarify warning message.
  resolve #4 add warnings to HikariConfig.validate() to inform user of misconfigurations, drop back to default values.