Adds initial support for hiding schemes and scheme sets
Adds defining hidden as part of a SchemeSetBuilder
Tests for schemeSetBuilder hidden property
Adds in batch visibility operations
Refactor the batch animation interface to make the APIs a bit clearer
Merge branch 'hidden-schemes' into release-1.1

Conflicts:
	Project Files/TableSchemerTests/TableScheme_Tests.swift
more fixes for 6.1.1
Only track batch animation state in debug
Fix some test method names
Adds two methods to TableScheme class to facilitate animations within a Scheme
Renaming / Doc update for batch TableScheme animations
Refactors private code out of TableScheme.swift into internal code for cleanliness
Conform ArrayScheme to InferrableRowAnimatableScheme
Doc indentation fix
Adds reloading schemes and scheme set functionality
withAnimation -> withRowAnimation for consistency
Updates the sample project with more animation examples
Some optimizations with the final keyword
Adds some safety mechanisms for working with scheme/schemeset visibility
Audits APIs to use implicitly unwrapped when they are required before use