C:\arduino-1.6\libraries\arduino-base64\Base64.cpp:2:26: fatal error: avr/pgmspace.h: No such file or directory
#include <avr/pgmspace.h>
^
compilation terminated.
I just got this to work last night. In the Base64 library open the Base64.cpp. Change the <avr/pgmspace.h> to "pgmspace.h" save and close. copy pgmspace.h into folder called pgmspace in your normal arduino libraries folder. If open close and reopen Arduino IDE. It compiles fine.
I also had to connect my GPIO0 like i was flashing firmware. All worked out great.