#315 Pushin some initial stuff
#315 show revenue model of post in posts table
#315 Saving revenue model working; appearance working
#315 make correct API call for Single Sales
#315 client-side validation for revenue model

ugly, but working poc implementation
#315 Handle visibility of revenue model selector
#315 Improving user interaction when setting revenue model
#315 a few styling fixes
Merge branch 'master' into feature/315_single_sale_purchases

Conflicts:
	laterpay/assets/css/laterpay-backend.css
	laterpay/assets/css/laterpay-post-view.css
Missing space
#315 Improved user interaction for switching revenue model

Also some entangled bug fixes for loading LaterPay JS libs
#315 minor improvements for setting revenue model
fixed php client signing
Merge pull request #322 from laterpay/php-client-fixes

fixed php client signing
Merge branch 'master' into feature/315_single_sale_purchases
add cp key to buy URL (fixes 404 on purchase)
#323 updated yui source url
#323 removed unnecessary vars
Add LaterPay (laterpay) to authors of plugin

laterpay is also added as comitter on WordPress.org
Merge pull request #324 from laterpay/feature/323_update_js_source_urls

Feature/323 update js source urls