Make no attempt to compress css/js files when building jsgui on Windows

[sjcorbett]

Could somebody with a Windows installation check that this works?

I expect:

• the build to succeed
• no *.min.{js,css}.gz files to exist in jsgui/target/*/

[buildhive]

Brooklyn Central » brooklyn #2299 SUCCESS This pull request looks good (what's this?)

[sjcorbett]

And there's me thinking configuring Maven plugin activation would be straightforward.