Fixed testing of plan id.
Updated code comment.
Added payee_name configuration parameter.
Removed NotNull requirement of selectedPlan field.
Added plan currency, plan cancellation button.
Added Stripe JS code.
Added disabling of buttons once clicked.
Added translation domain for plan names.
Increased Symfony dependency requirement to all 2.x series releases starting from 2.2.
Cleaned up parameter definitions.
Added README.