Added new AddChildToEntity action
Created a special SamplePanel for TextComponent
Minor code changes.
Condition removed from effect
Abstract control structure effect added to be the parent of all control structures
ScriptCall refactored to be a control structure
If effect
If-then-elseif-else
while
bindings
initializer
test updated
Merge pull request #576 from jtorrente/effects-controlstructures

Control structure effects
Group all engine-related objects into Engine control class
Changes after API changed
GameView converted to interface
Changes after API change
Added widget to show the engine
Some cleanup in engine initialization
Avoid accumulating clicks in edition mode that have consecuences in test mode