Removed lazy param and isConstant from operations
Reverts "cannot change reserved vars" rule. This should be enforced
in the editor (when creating user vars), but not in the engine.

The current restriction breaks runtime language change via effects.
Added TextComponent, as generic class to deal with expressions
LabelComponent supports expressions
TextButton supports expressions
Updated initializer
Simplified methods to create icons buttons
Refactor in buttons creation
Fix bug in IconButton
Bug fix in ReorderSelection
Bug fixes in camera and debugview
Merge pull request #642 from anserran/opsimpl

Removed lazy param and isConstant from operations
Merge pull request #647 from anserran/sbf

Bug fixes related to enable state in icon buttons
Merge pull request #648 from anserran/camerasfix

Bug fixes in camera and debugview
Merge pull request #638 from anserran/varsintext

Labels now process expressions in texts
Merge pull request #644 from manuel-freire/fix-reserved-vars-immutability

Reverts "cannot change reserved vars" rule. This should be enforced
Removed behaviors
Behavior converted to a component
API changes
Tests fixed