Fix Payment Custom Adapter tests
Enable some disabled tests
Paginator should not go below zero when there are only few pages
Finish 4.11.17
Merge pull request #197 from onddo/tests-fixes-2

Some test fixes (2)
logMail() method had param $subject two times
Undefined index fix
Array to string conversion fix
Missing $subscription param added
Missing transaction param added
Added missing params
Paypal payment adapted missing array indexes added
Missing params added for 2checkout test
Added missing variables for Webmoney test
Webmoney payment adapter changes:
title changed to serie_nr
Added missing testMode property
Removed test which was causing PHP Warning
Finish updates of tests
canChangeCurrency() method updated
tests for canChangeCurrency() method updated
Finish canChangeCurrency() method fix