Command in "Configure element with command line tool" can't contain double quotes

Scenario:

1. Open the Workflow Designer.
2. Click "Create element with command line tool" button on the toolbar.
3. Fill the wizard somehow. The "Command" field should contain double quotes:

   "%UGENE_JAVA%" -version

4. Accept the wizard.
   Expected result: the element appears on the scene.
5. Launch the workflow.
   Current result: a SAFE_POINT is triggered:

   Trying to recover from error: File '/Users/atiunov/root/projects/trunk_5_shadow_debug/src/_debug/ExternalToolConfig/Custom_cmdline_worker_1.etc' contains mistakes at ../../../../trunk_5/src/corelibs/U2Lang/src/support/WorkflowRunTask.cpp:170
   

The created element also can't be parsed on the UGENE launch. Parser in its actual state can't process values with double quotes. Add a possibility to escape double quotes in files.