unsupported JDK when containing spaces

Using the default JDK path like C:\Program Files\Java\jdk1.8.0_112 prevents Nuxeo from starting up.

This happens in Windows when nuxeoctl is run under cygwin. This also happens under unix.

1. setup a java folder like export JAVA_HOME="/Users/myusername/here space"
2. try to launch nuxeo
3. it fails with:

   ./nuxeoctl start
   Erreur : impossible de trouver ou charger la classe principale espace.lib.tools.jar