I2C Slave v0.3.3

Changes from v0.3.2:

• fixed analog_read example to use signed int unpacking in Lua script
• added comments for Lua string.unpack conversion options
• this release should finally have matching dirnames for Arduino IDE example inclusion
  -- (0.3.2 had a messy release that should've fixed that but didn't)

This should (hopefully) be the last of the rapid-fire releases that follow library registry inclusion.

I2C Slave v0.3.2

Changes from v0.3.1:

• fixed example directory naming in line with Arduino IDE expectation
• added complete license text and opening comments in source files
• minor README fixups

I2C Slave v0.3.1

Release in preparation for publishing to the Arduino IDE Library Manager.

Changes from v0.3.0:

• updated Lua examples to use more elegant string packing/unpacking