Spoofax/928: allow users to choose their own JVM options.
Spoofax/928: fixes for bugs introduced by previous commit.
Eclipse feature 'org.strategoxt.imp` now only comes with language DynamicRoot.
Bugfix: language name was null when languageCount == 1 and the language doesn't specify JvmOpts
fix
Add default Jvm opts to language properties.
Merge pull request #10 from metaborg/Spoofax/928

Spoofax/928: allows users to choose their own JVM options.