TSL2561 light sensor library

The TLS2561 is acalibrated, integrating light sensor, connected by I2C, usinf 3.3 V (5 V modules are available). It has a broadband an IR sensor, which allowes to calculate the light level in lux using a given formula.

This library allows to:
 - chose sensitivity automatically or manually
 - read the raw values
 - convert raw values to lux unit
 - chose between keeping the sensor enabled (instant readings) or using power safe between access

See License.txt for a license.

Thanks to Adafruit for providing example library code. This is a rewrite of their library and cleared to use a different license.