Debugger separated into a PureScalaDebugger and SubScriptDebugger

In order to make Gradle work with it, go to the build.gradle of the project you want to debug, locate the ```task(debug, dependsOn: 'classes', type: JavaExec)``` line there, locate its property ```main```. In order to debug with pure scala debugger, set ```main = 'subscript.swing.PureScalaDebugger'```. In order to debug with SubScript debugger, set ```main = 'subscript.swing.SubScriptDebugger'```.