Context and Sandbox widget: preliminary tests to fully seperate global instances of Builder, Cache, etc. Right now, only Builder is tested.
sandbox: enhance sandbox separation, and add ExceptionManager into the sandbox management too.
sandbox: add a little comment for explaining the example
wip sandbox with clock
sandbox: ensure the container is created, and fix clock
Sandbox-clock fixed
Commit
merge master
sandbox: add some documentation.
sandbox: add documentation generation + register sandbox