Espruino 1v91 released

Just a quick note to say that Espruino 1v91 has been released.

Changes in this one are:

Bugfixes on ES6 features

• Fix error handling in promises (returning pre-rejected promises)
  
• Allow arrow functions inside nonexecuting functions
  
  

General improvements

• Fix potential bugs with saving code to flash memory
  
• Allow HTTPS to work without a certificate specified
  
• Remove some global variables that were defined in devices that didn't support them
  
• BBC Microbit: Update Espruino with pin polarity, so saved code gets loaded without BTN1 pressed
  
• ESP8266: Fix regression that stopped 1v90 from working
  
• Added Global built-in objects like SPI1/Serial1 and Bluetooth to the index of the reference
  
• Ensure tab complete/others include the Object proto even on functions/strings
  
• Allow implicit conversion of hexadecimal strings to numbers
  
  
  

Puck.js improvements

• Add NRF.setLowPowerConnection(bool) to allow low power continuous connections to Puck.js
  
• Making getPrimaryService more robust, with better error messages (for connecting to other pucks)
  
• Added NRF.getAddress() - to get our own MAC address
  
• Increase custom UUID count from 3 to 10 (when reading devices like Awox that use lots of custom 128 bit UUIDs)
  
• Tweak battery percentage calculation to try and make it more linear
  
• Adjust Puck.light() levels based on battery voltage
  
• Fix E.hwRand()
  
• Add NRF.restart() to force the restart of the Bluetooth Softdevice if required