Create block for TFMini rangefinders

[dlcarrier]

The TFMini rangefinders work with a collection of blocks, but to bring it in line with support of other products, it would need a single block, likely with I2C and serial support. They use the same protocol, so a single code base should work. The product pages are at: https://www.parallax.com/product/28350 and https://www.parallax.com/product/28360