Update Buttons section of README

Referencing `$button-style` hook that was removed in ca2b6170a3ee399824d254e52a021d8d72cf9fe3
Bump minor version to 0.10.1
Replace en-dash with regular dash
Merge pull request #100 from ecbypi/update-readme-buttons-section

Update Buttons section of README
Refine README, LICENSE and CONTRIBUTING docs