Implement .paypal command

Summary: Code contained logic procedures, but not the dcc binds to call them.

Test Plan:

00:04:44 <Dereckson> .paypal 100
00:04:44 <daeghrefn> Net:    96.37
00:04:44 <daeghrefn> Gross: 103.75

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1565