Copied TODOs to GitHub issues, removed some TODOs

TODO.md

@@ -1,17 +1,12 @@
 #PCB TODO
 
-* Back board: move GPIO expander to back
-* Back board: move GSM modem to back to back
-* Back board: move charging board to front
-* Footprint for smaller MCP23017?
-* Change via drill/annular ring size near pads to make rework less problematic
-* Audio amplifier footprint?
-* UART buffering?
-* Comparators for voltage level measurement (DC-DC overcurrent, incapable charger, main battery shutdown)
-* Replace RGB LED by WS2812?
-* Add diodes on keypad board
-* Switch on USB power - power USB from charger 5V input when on charger (starting with this)[http://www.ti.com/lit/an/slva716/slva716.pdf]
+* Change via drill/annular ring size near pads to make rework less problematic ( #5 )
+* UART buffer addition ( #6 )
+* Comparators for voltage level measurement (DC-DC overcurrent, incapable charger, main battery shutdown) ( #7 )
+* Replace RGB LED by WS2812 ( #8 )
+* Add diodes on keypad board ( #9 )
+* Switch on USB power - power USB from charger 5V input when on charger ( #10 )
 * Add more clarifications to the board schematics
-* Add silkscreen + marks for polarized capacitors
+* Add silkscreen + marks for polarized capacitors ( #11 )
 
-![Cat picture to make it less boring](https://cdn.pixabay.com/photo/2014/03/29/09/17/cat-300572_960_720.jpg)
+![Cat picture to make it less boring](https://cdn.pixabay.com/photo/2014/03/29/09/17/cat-300572_960_720.jpg)