Espruino 2v13 released

Another big release! Full change list is at http://www.espruino.com/ChangeLog but the highlights are:

• Big RAM usage improvements (especially for arrow functions)
  
• 3% speed improvemt
  
• Added String.concat
  
• Bangle.js 2 has a much improved Menu UI
  
• You can now do g.fillRect({x,y,x2,y2,r}) for rounded rectangles
  
• String.toUpperCase() and .toLowerCase() now work for accented ISO8859-1 characters
  
• Bangle.js 1+2: Add 'back' option to E.showMenu, E.showScroller and Bangle.setUI
  
• Bangle.js 2: Update E.showPrompt with a bigger touchable area around buttons
  
• Util Timer now runs independently of system time. More accurate on nRF52
  
• Bangle.js: Battery discharge curve is now scaled better
  
• Bangle.js: If home button held and JS is still executing, force a break (like Ctrl-C)
  
• Bangle.js 2: Add visual feedback when showPrompt button is pressed
  
• Fix another potential Storage compaction issue
  
• Bangle.js: default 'locale' now supports second 'dp' argument for decimal places
  nRF5x: Fix merging of packets for NRF.findDevice
  
• Bangle.js2: Unistroke recognition accuracy improvements
  
  

To get it:

• On Bangle.js 2 use the firmware update app
  
• Or you can download in the usual way from https://www.espruino.com/Download