Implement HiDPI

[asfimport]

@pmouawad (Bug 59168):
Following improvements made in #3674, this bug is created to take into account the following proposals from Benoit Wiart:

on macos loading @2x resources is supported since jdk8u20

• see https://bugs.openjdk.java.net/browse/JDK-8011059

The user should not choose a different size in the properties to get hdpi support.

hdpi image is coming to jdk9

• https://bugs.openjdk.java.net/browse/JDK-8046010

• http://openjdk.java.net/jeps/251

• do not mix image size and hdpi

• use the "standard" of @2x, @3x convention for the images instead of the <SIZE> hack.

• use a single code path to load icons : it will allow caller to know nothing about hdpi
  for example the caller want to load /status/myimage.png

if in hdpi the icon loader will try to load /status/myimage@2x.png if not found it will fall back to /status/myimage.png

it will allow third party plugins to progressively provide @2x resources

Some help, it's old and only cover macos but ...
http://bulenkov.com/2013/06/23/retina-support-in-oracle-jdk-1-7/
http://bulenkov.com/iconloader/

OS: All

Depends on:

• Improve display of JMeter on high resolution devices (HiDPI) (part 1 of enhancement) #3674