🐛 Fix bash version check (#51)

The bash version check was performed before declaring the
emoji array, so an error message was displayed by bash
before printing the custom error message. I also changed
the exit code to 1 (error) in the case of an old bash version.

Merge pull request #41 from louib/better_replace_function

😹😹 Improve tokenization

Minor changes to readme

Merge pull request #10 from JackDanger/danger/usage-list

Print list of supported emojis

Merge pull request #11 from zmwangx/support-plus-minus

Update regex to account for 👍 and 👎

Merge pull request #2 from cremno/fix-conversion-of-emoji-names-conta…

…ining-0

fix conversion of emoji names containing 0