Remove need for once
Removed autoCancelPrevious

This has turned out to be superfluous. `memwatch` does not reveal any
memory leaks while running test coverage. Specifications pass. However,
the behavior of the equality binder changed, but appears to be logical.
Revert removal of autoCancelPrevious for binders

These appear necessary for Montage until further notice.
added a string concat example
used jasmine-node spec/readme-spec.js

to test the strings example
Add failing test for has binding on maps
Fix has observer for maps
Update lingering references to items to entries
added contenteditable
Permit whitespace in additional positions

Particularly within and around records.
Fix null cases for string contains operators

Previously, startsWith, endsWith, and contains observers would throw an
exception if the input was undefined.
Restore parser memoization table
Clone syntax trees

Montage depends on them to be mutable.
Tighten the version predicate for Jasmine

Tests break in 1.14.0.
Remove need for once
Guard against non-array-likes in makeNonReplacing
Do not clone syntax trees

This is currently necessary for Montage to pass tests, but those tests
are no longer valid and will be updated before adopting a new version of
FRB.