Improve spectro for quantum dots

[lpatiny]

• Add -3.3v : voltage for UV led #1
• Control led from I2C to liberate some pins (A0, A1, A2, A4): Control the LEDs from I2C in order to control the max intensity #53
• Allow bluetooth / GSM - GPRS module and connect A0, A1, A2, A4
  • Take care that the module is just behind the screen especially in a metallic case !!!
  • It will use SoftwareSerial
• GSM / GPRS module consume a lot of energy !!! They need to be directly connected to the battery.