don't need end-php
merchandId and mechandKey are retreived from ini file
added validateSha1 method
add .php to ini file to prevent reading through webserver
Merge branch 'master' of https://github.com/stefanvangastel/CakePHP-SisowIdeal

# By Stefan van Gastel
# Via Stefan van Gastel
* 'master' of https://github.com/stefanvangastel/CakePHP-SisowIdeal:
  Added example ini file and added description and additional step to README. fixes #1
Merge pull request #2 from joostdekeijzer/master

Several changes