update for latest RC (optimizely#238)

Refact: Copying attributes into new copiedAttributes variable (optimi…

…zely#227)

* Refact: Copying attributes into new copiedAttributes variable

* changed description of copyAttribute function

chore: release 2.1.1 (optimizely#195)

* Fix impression sent from feature experiment variation toggled off. (optimizely#193)

chore: release 2.0.2 (optimizely#194)

* Fix impression sent from feature experiment variation toggled off. (optimizely#193)

Update date (optimizely#190)

prepare for minor bug fix release (optimizely#181)

* prepare for minor bug fix release

* fix hurried changelog entry