JS: add explicit doubleValue() calls to the OutputHandle getter code
JS: add explicit doubleValue() calls to the OutputHandle getter code

Some compilers (eclipse luna) seem to have a hard time with the return type here
and say the conversion is invalid, add explicit .doubleValue() calls similar
to the Object wrapper version that appear just before.

Signed-off-by: Harvey Harrison <eadbd6b462bf3c97df0300a934c12bc2e5d1fe51@ausenco.com>

jaamsim/jaamsim,jaamsim/jaamsim,jaamsim/jaamsim,jaamsim/jaamsim