JBIDE-14465 common.model.ui.test fails with Kepler M7 TP

preference page is not loaded because compatibility layer
is missing during tests execution
Fixing stacks test case, using potential new pre-stacks.yaml file
JBIDE-14444 Drag & Drop of image into HTML editor - h:image
Revert "JBIDE-14405 moving WaitJob out, and also moving ECFTransport impl details into a private class"

This reverts commit 1250eb92ab20f0d06d9a614428ed0d5c85fce1ae.
Revert "JBIDE-14405 moving WaitJob out, and also moving ECFTransport impl details into a private class"

This reverts commit ab0f3743befe40ff7cfddfe5ea0e3f2368bedb74.