Riseup's EE certificate expired (EE = End-Entity, the commercial
certificate signed by the issuer), and we weren't able to fetch
provider.json because the pin wasn't valid.

This problem needs to be avoided in the future, using
HKPK (https://tools.ietf.org/html/rfc7469), which Micah's implementing
on Riseup.

Switching from build types from flavors enables us to run tests against
production apk, not just debug. I didn't detect this pinning problem
because tests were run only against the debug apk, which trusted
preseeded providers by default (thus bypassing pinning issue).

Sometimes, the emulator is so slow (I wish genymotion was open
source...) that even though everything's going OK tests fail because
they don't wait enough.

testVpnButtonIsDisplayed and testVpnIconIsDisplayed fail because calyx in testVpnEveryProvider fails, but if you run them alone they pass.

Give more time to provider details fragment to appear, because debugging makes the code run slowly.

And checks in controllers, so that if a button isn't shown, I throw a
new IllegalStateException. This helps to trace the error.

This way, I can add more easily the tests for errors.

Next step: beautify.

Tests click new button, instead of action bar's.

Fixing more bugs...