Handle missing descr in Rabobank restructered files

Some files actually have no REMI token in the 86 record, and therefore
we end up with a NoMethodError for Nil-exception. So, if that is the
case, we simply set no description at all (there seems to be no sensible
alternative).
Do not leave \r lying around
Add Rake as development dependency

The README notes to run tests with `bundle exec rake spec`, which
actually fails unless you add Rake to the gemspec as a development
dependency.
Merge branch 'missing-descriptions' into next
Merge branch 'rake-dependency' into next
Merge branch 'proper-newline-splitting' into next

Conflicts:
	lib/mt940/banks/rabobank.rb
Handle 7 or 8 digit bank account numbers
Merge branch 'handle-shorter-bank-account-numbers' into next
Read BICs from ACCW tags in 86
Merge branch 'bic' into next

Conflicts:
	lib/mt940/banks/rabobank.rb
	spec/fixtures/rabobank_mt940_structured.txt
	spec/mt940_rabobank_spec.rb
fix case for rabobank when description has several lines and it starts from number; fix handling names containg slash
fix for rabobank structured MT940 case with slash inclusion to description