Issue #104: Add category_uid to base of compiled class definition

[rmouritzen-splunk]

Changes:

• Issue Add category_uid to base of compiled class definitions #104: Add category_uid to base of compiled class definition.
• Fix edge case with profiles using attributes with observable by attribute definitions. When "compiling" profile attributes, attributes with observable by dictionary attribute were not being copied to the profile's attributes. Basically the attribute's observable member needs to be copied.
• Minor dependency updates.
• Version bump to 2.73.0.

[rmouritzen-splunk]

FYI: @davemcatcisco , @dkolbly, and @query-jeremy.

This change adds category_uid to the base of each compiled class, as requested by Donovan Dave. The category_uid defaults to 0 for undefined or missing categories. This happens with base_event since it uses the other category, and other isn't defined in the schema -- it isn't defined in categories.json.