Added resetPendingEvents to getEvents
Refactored KEEN_LOGGING_ENABLED macro
Merge pull request #40 from keenlabs/31-nsdateformatter-is-not-thread-safe

Refactored NSDate formatting to be thread safe
Merge branch 'master' into 33-keen-logging-enabled-macro-is-misdefined
Merge pull request #41 from keenlabs/33-keen-logging-enabled-macro-is-misdefined

Refactored KEEN_LOGGING_ENABLED
Merge branch 'master' into 39-reset-pending-events-should-be-called
Merge pull request #42 from keenlabs/39-reset-pending-events-should-be-called

Added call to resetPendingEvents in getEvents
Refactored convertNSDateToISO8601 to accept date strings