Document alternate.
Fix typo that broke Android.

We copied script_version.rpy onto script_version.rpyc, which
made things fail to start on Android.
Report NO_RAPT before NO_JDK.

On Windows, RAPT is responsible for detecting the JDK. If RAPT is
missing, the JDK will also be reported missing - even if it's
installed.

Changing the reporting order makes this less confusing.
Fix sense of environment-encoding test.