Fix jetty filelocking on windows

Jetty by default memory maps files
and windows locks memory mapped files
as a result it it not possible to save a file on windows
when jetty is running.

See also https://www.assembla.com/spaces/liftweb/wiki/Fix_file_locking_problem_with_jettyrun

Signed-off-by: Davy Meers <davymeers@hotmail.com>