c-generic/libpubnub: Move the signing to crypto.c:pubnub_signature()
c-generic/libpubnub: Make all debug prints really go to stderr
c-generic/libpubnub: Add support for AES256 encryption when cipher_key is set
c-generic/libpubnub: Add gitignore for generated files
c-generic/libpubnub pubnub_sync_done(): Avoid leaking sync->{response,channels} using newly factored out pubnub_sync_reset()
c-generic/libpubnub pubnub-sync.c: Include pubnub-sync.h for better consistency guarantee