Commit in scope of issue :  Issue #104 
Changes in commit:
1. Refactor core to Event Api. All core parts will communicate with each
other through SCWeb.core.Environment object. 
2. Introduce all required events. They available in SCWeb/Core/events
folder. 
3. Introduce Sandbox component which is connected with core. Each new
plug-in component have to communicate with core with help of Sandbox
component. The implementation is available in SCWeb/sandbox folder.
4. Introduce new version of adjusted scn-viewer according new sandbox
API.
Not available in commit:
1. scs, scg, txt, image, html, youtube, etc ... plug-ins have not
refactored to new sandbox API.
2. Problem with two equal request to the server appear after
refactoring.
3. Multi-window interface is not working. 
4. Plug-in registration process is not refactored yet.