Get JNIEnv in thread-aware manner.
Minor comment added for iOS Facebook Login type
Merge commit '1c320d06a3f18ad1250c0eabe627739fbe6b1f51' into LFL-DD-Teak
New JNI getEnv() method for Teak
New JNI getEnv() method for Facebook
New JNI getEnv() method for Sharing