Actions and checks required prior release of version 1.6.0

• Merge Adding Sharp GP2Y0A21F_5V_DS #17.
• Merge Nano board Atmega 328 is not tested in continuous integration #19.
• Update version number and changelog on README.
• Add "and contributors" to README and LICENSE file and license headers modified code files.
• Update dates on copyright notice of LICENSE and modified code files.
• Update library.properties file.