Change event_code field limit

So that the dispute notifications from Adyen can work.

'NOTIFICATION_OF_CHARGEBACK' event_code is 26 characters long, which
exceeds current limit.
Merge pull request #62 from pjg/fix_event_code_database_field_limit

Fix dispute Adyen notifications
Fix nokogiri dependency for 1.8 and lower.
Fix typo
Use https in Gemfile.
[Travis] Don't try to use Rails 4 on Ruby < 1.9.3
[Travis] Also run tests on RI 2.0.0
Require RSpec 2.14.x and fix deprecations.
Merge pull request #63 from wummelkiste/master

Add support for fraud offset, client side encrypted cards
Make specs green.
[gemspec] Add accent to Eloy’s surname.
[README] Add accent to Eloy’s surname.
[gemspec] Add MIT license.
[rake] Add task to update CA root certificates file and run on each release.
Released adyen gem version 1.4.0.
[API] Update CA root certificates file.
[rake] Fix update CA cert task.
Use bundler for gem management tasks.
[API] Update CA root certificates file.
Merge branch 'master' of https://github.com/wvanbergen/adyen