Latest Espruino build for Esp8266

It went through 2 phases:

• Switching from the included maths libraries to GCC's libs
  
• Finding out GCC's libs were HUGE and adding my own (small) implementations of the biggest ones if SAVE_ON_FLASH is defined
  
  

So I think ESP8266 is currently using GCC's libs, but hasn't replaced the big ones with small ones.