Minor edits to README.md
Minor edits to README.md

Edited for formatting, spacing, and descriptive headings for Bats helpers/commands/functions.
ev3dev/bats,Tiger66639/bats,thomasleveil/bats,aerickson/bats,jszwedko/bats,rvesse/bats,Anvil/bats,Sylvain303/bats,msabramo/bats,bpkg/bats,mjhsieh/bats,ztombol/bats,sstephenson/bats