Fix SortedArray length update on push pop

Fixes #64
Iterate maps and objects properly
Remove deprecated map items method
Take beter care to use swap instead of splice

In observable arrays, to avoid unnecessary allocation.
Fix initial state check for property observers
Ensure that v2 does not get published to npm as latest
Allow object holes to be treated as undefined

For the purpose of Object.equals tests on object literals.
Previously, {x: undefined} and {} were not considered
equivalent.
Fix #64
Make heaps update length on delete
Fix length getting out of sync when deleting from an empty heap
Always use swap for splice

Existing logic was more complex than necessary.
Phantom is not yet ready for Jasminum.
Update change log
Disable Node.js v0.8 integration tests

Travis now errors because of a bad npm certificate.
Add test case for #66
Add initial LFU
Add LfuMap
Make LfuSet variables more descriptive
Update readme to contain Lfu{Set, Map}
Port LFU to v2 branch conventions