resolve #23 "support size-in-bytes type"

• fix issue #22 "literal duration captured as string"
• code cleanup: generate code as part of test phase

Some minor bug fixes; simplified generated code and additional tests

Code simplified, more consistent and better organized. All tests reviewed and coverage further increased (to 95%).

including some internal code cleanup

This is almost a complete rewrite of the tool! Thanks to that, now supporting lists, optional objects (sections), and hopeful making easier to further extend the tool later on.

• resolve #16 "rewrite code"
• resolve #15 "support list"
• resolve #10 "annotations" -- basically only the #@optional one
• NOTE: toString not generated anymore

• fix #13 "scala: double definition"
  add build auxiliary method to avoid type erasure issue in case of optional member
• --noToString now processed for scala
• add options --toPropString and --noToString (only processed for java):
  • --toPropString to generate toPropString method (not generated by default)
  • --noToString to not generate toString method (generated by default)
• fix #12 "incorrect reference with standard types in path fragments"
• java: factor out access to Config parameter for sub-section in static method __$config at the root class
• in java's toString, no need for conditional for string field if required or with default (non-null) value
• allow missing sections in given input configuration.
  This helps with sections whose all members are optional.
  Still to be done is proper handling of optional sections in general. Besides an explicit annotation
  to indicate that a section is optional, note that a section can also be implicitly optional
  if all its members are optional.
• fix #11 "name collision with no-arg methods in scope"

Implements #8 (support for durations, see readme) and #6 (generation of config templates)

So, having "config" as fragment of any configuration path is now properly handled.