Investigate potential login issue. Provide feedback when loading.

[weilu]

"Do you know about any issues connecting the bitstamp app? Clicking the Login button does not seem to react, some kind of feedback would be good. Otherwise, great app."

[thatguy11011]

Having the exact same issue, surprised more people haven't mentioned it :S

[mmazi]

Logging in works for me now, and the app seems to work smoothly. You need to create an API key first though.