add a test page with some keys and PGP blobs

this makes testing the work-flow more easy. For now you can serve this
by running `python -m SimpleHTTPServer` in the `spec/` directory. A
serve task to grunt might be added, later.
make testing in firefox more easy

There is now a test profile that can be used for development. There is one
key (public and private) preconfigured and the test page is also added by
default. Also the test page is added as a bookmark to open it easily.
cleanup readme

use correct citation (intepret this as code, not as citation)
add grunt-contrib-connect as a simple http server

this is great for running a local server to speed up development.
remove --keepalive option

this can be achieved more elegantly by adding keepalive as a "sub-task"
add new unknown key

the old one seems to be broken somehow, at least, it triggers an exception.
Leaving the "broken" one in, since it’s a good test.
Merge branch 'feature/tests' into feature/verify_signatures
rename some private variables in verifyFrame

those variables came in by copy & paste and should have been renamed.

Also the removeDialog method needed to be fixed. Calling this method just
did nothing. Now the dialog will actually be removed.
move openpgpjs dependency from controller

all this should be handled in pgpViewModel. Now the model can verify
cleartext messages, which is used to implement verification within the
controller.