Qualified version

In some situations the plugin needs a qualified OSGi version. The plugin will first use the explicitly provided version. If this is not set then the plugin will generate a qualified version. First it will re-use a qualified OSGi version from Tycho if the project is built using Tycho. Otherwise the project’s version is used and the -SNAPSHOT suffix will be removed by the current timestamp. This also means that non -SNAPSHOT versions have to be OSGi compliant.