Fixes related to the empty set to pass tests
Added release notes
Updated deps
Autogenerated markdown documentation
Setting version to 0.5.0:

This is a release for the Dynamograph project. Some of the major changes:

* Moved ops to a separate folder and added new ones:
    * Added Pop which is the same as Lookup, but removes the element from the set
    * Added Choose which chooses (projects) a subset of a given type
    * Added Reorder which is same as Choose, but for equivalent sets
    * Renamed Union and Subtract
    * Union unicode symbol (\cup)
* Added construction for bounding type-set by a type-union (every element is one of ...)
* Migrated records and props from scarph and tabula
Merge branch 'release/dynamograph'
Merge branch 'master' into experiment/records

Conflicts:
	src/main/scala/TypeSet.scala
	src/main/scala/package.scala
	src/test/scala/RecordTests.scala
	version.sbt