Fix recursive merge include bug.

Fix merge include bug. Remove support for legacy Python

Merge pull request #34 from JCSDA-internal/feature/query-value-as-var…

…iable

Allow variable in include query value string

Improve yp-preprocessor

Fix stdin bug. More logging.

Add preprocess command

Fix root level include merge variable subs

Improvement on INCLUDE scope usage.

Fix root level include scope variable issue.

Include scope variables. Merge include. Non-string variable subs. YAM…

…L 1.2.