Added Spade.iterators property.
Added iterator function for SCAN.
On branch iterators
new file:   lib/iterators/index.js
new file:   lib/iterators/scan.js
modified:   lib/spade.js
v0.48.0.
Added #loadIterators to simplify iterations through keys with SCAN, ZSCAN, HSCAN commands.
Added Spade.iterators#scan example.
Updated Gerry dependency to v0.6.1, collect all events if specified in the constructor.
Fixed 'polling' events, don't collect events and arguments for default, only for tests.
Fixed debug events, it is better to emit event before callbacks.
On branch iterators
modified:   Readme.md
renamed:    example/spade-all-connection-events-example.js -> example/connection-all-events-example.js
renamed:    example/spade-connection-events-example.js -> example/connection-example.js
renamed:    example/spade-dummy-example.js -> example/dummy-example.js
new file:   example/scan-iterator-example.js
modified:   lib/iterators/scan.js
modified:   lib/spade.js
modified:   lib/tasks/connection.js
modified:   package.json
modified:   test/auth-fail-test.js
modified:   test/auth-invalid-test.js
modified:   test/auth-no-select-test.js
modified:   test/auth-select-ok-test.js
modified:   test/cache-test.js
modified:   test/db-fail-test.js
modified:   test/db-selection-test.js
modified:   test/monitor-polling-task-test.js
modified:   test/pubsub-multiple-sub-multiple-unsub-test.js
modified:   test/pubsub-offline-test.js
modified:   test/pubsub-offline-unsubscribe-all-test.js
modified:   test/pubsub-ping-test.js
modified:   test/pubsub-polling-task-test.js
modified:   test/pubsub-subscribe-test.js
modified:   test/pubsub-test.js
modified:   test/socket-reconnection-test.js
modified:   test/task-polling-hangup-pubsub-test.js
modified:   test/task-polling-hangup-test.js
modified:   test/task-polling-reconnection-test.js
modified:   test/task-polling-test.js
modified:   test/transaction-multi-rollback-test.js