Merge pull request #362 from sortega/default_okpay

Use public okpay mock by default in the GUI
Load configuration from /etc for the okpay mock
Merge pull request #363 from sortega/configurable_okpaymock

Load configuration from /etc for the okpay mock
Completely remove mockito from the project
Merge pull request #364 from sortega/unmockito

Completely remove mockito from the project
Change configurations to use the trial environment by default
Merge pull request #365 from sortega/trial_env

Change configurations to use the trial environment by default
Workaround for the label-with-graphic javafx bug

Labels with graphics randomly fail with javafx 8 so this change replaces
the one in WalletBalanceWidget with an HBox containing an image and a
label as a workaround.
Merge pull request #366 from sortega/wtf

Workaround for the label-with-graphic javafx bug