Allow tests to be associated with multiple Pre-Conditions

Although the plugin allows to more than once pre-conditions to the test, when displaying the test only one of them is shown.

The plugin should either not allow to add several pre-conditions or display them all.

I have tried to reproduce this issue in your project by creating a precondion XRAY-248. My intention was to add this to the test issue XRAY-230. Seems like i dont have the sufficient permissions to do so.