Fix tests

First I have established CI on travis-ci, then I made Danish bank tests working again.

Most importantly, we either shouldn't compare .id against an absolute value (because hash() doesn't have guaranteed constant value and really it is changing with every version of Python), or use hashlib.sha256(), but I wonder if the latter is necessary, so I am suggesting the former.

https://travis-ci.org/mcepl/ofxstatement/builds/3960432