Add rspec test stuff
Refactor ssh_keygen function

Totally refactor the ssh_keygen function to make it more predictable and
debuggable. This refactoring fixes a couple of bugs, but makes it
interface-incompatible to its previous versions. Therefore classes using
it need to be adapted.
require name argument only for actions acting on keyfiles
Move storeconfig based known_hosts implementation

If the server has no storeconfig enabled, but a class collecting and
exporting virtual resources is defined, the server complains loud about
this circumstances. Therefore this commit moves the code to a different
class which is only included if required.
Fix syntax error
Fix undeclared variable error
Use the new ssh_keygen api
Update changelog and version