initial commit
coments for most of functions
some documentation checked
more documentation, merging
Fix notfound
more fixes
fixed tests, docs
polishing
fixed examples
global update
cursors and ref created
Change interface to reference
Merge pull request #47 from vacuumlabs/cursors

cursors and ref created
rename allowMissing to missingOk
remove unecesary
added new line to cursor.dart
rename Persistent to PersistentCollection
added PersistentIndexedCollection
dissoc on sets and vectors
reduce description added