Rename water.parser.Enum to water.parser.Categorical, because Weaver was confusing it with java.lang.Enum.
Last big change to the REST API infrastructure: handler methods now accept Schema objects rather than their backing objects, and lots of gratuitous Iced POJOs have been removed.
Slight tweak to PCAV2 given the new changes.
Generate Markdown docs for all the schemas, and a TOC Markdown doc for the endpoints.  Also improve the endpoint Markdown.
Remove the default value for K in KMeans.
Do Schema field validation at startup time.
Removed all non-Schema Iced types from all schemas.
Fixup after merge.
Add typed keys: Key<T extends Keyed>.
Step 1 of Key<T> in the Schema layer: mechanism is in place, and ModelMetrics.frame is converted.
Step 1 of Key<T> in the Schema layer: ModelMetrics.model is converted.
Switch ModelParameterSchema to use FrameKeyV1 for the frames.
Unbreak hex.AAA_PreCloudLock by calling H2O.registerAllSchemasIfNecessary() as late as possible.
Replace all Key schema fields with properly typed KeySchema fields.
Put h2o-package output file in .gitignore.
Merge branch 'master' of https://github.com/h2oai/h2o-dev

Conflicts:
	h2o-core/src/main/java/water/api/RapidsHandler.java
	h2o-core/src/main/java/water/api/RapidsV1.java