added migration for old postmetas to new postmeta-array, fixed loading, fixed smaller bug on activation to remove laterpay-navigation on failing requirement-check #198
Merge remote-tracking branch 'origin/feature/91_post_type_support' into feature/91_post_type_support

Conflicts:
	laterpay/library/laterpay/LaterPay/Core/Bootstrap.php
	laterpay/library/laterpay/LaterPay/Helper/Pricing.php
removed unused debugging statement #198