Clarify that CreateConstructorAlias() makes a ‘constructor alias’

The original comment says that it creates a ‘function alias’ but this
will be confusing if we implement functionality to create aliases for
functions that are not constructors.  It is better to make the
commentary for CreateConstructorAlias() more explicit.
Allow function aliases in dialog scripts

This patch provides a utility for creating function aliases that we
can use in dialog scripts.  It is similar to how we create aliases for
class constructors.  The only difference is that it makes an alias for
an arbitrary function and not a class method.  So for example if we
add the code

    LNVL.CreateFunctionAlias("changeToScene", LNVL.Scene.changeTo)

then we can use ‘changeToScene()’ in our story scripts instead of the
more verbose ‘LNVL.Scene.changeTo()’.  This is more economical in
terms of key-strokes, without sacrificing readability, and it helps
hide implementation details such as the underlying engine function
that we really call.
Alias LNVL.Scene.changeTo() to the function changeToScene()

This creates the changeToScene() function for dialog scripts to use.
It calls LNVL.Scene.changeTo() behind the scenes but is easier to read
and write.  The patch also updates all of the example scripts using
the function and the Howto documentation.
Make ‘Color’ an alias for ‘LNVL.Color’ in dialog scripts

The LNVL.Color module provides short-cuts for color names so that we
can write things like LNVL.Color.NavyBlue in scripts.  Now that we run
scripts in their own environment we can take this short-cut a step
further and create an alias ‘Color’ table so that we only need to
write Color.NavyBlue, omitting the ‘LNVL’ prefix.  This patch adds
that alias and updates all example scripts and the Howto document.
Create ‘changeSceneBackgroundTo()’ alias

This is an alias for ‘LNVL.Scene.changeBackgroundTo()’ and exists for
consistency with other aliases we made to help remove all of the LNVL
prefixes from scripts.  This patch also updates the one example script
that uses this function.
Use title-case for function aliases for consistency

We write constructor aliases in scripts in the forms Scene(),
Character(), Menu(), and so on.  For consistency we therefore use
ChangeToScene() instead of changeToScene().  This patch changes the
case of such aliases so that they all begin with capital letters.
Merge branch 'function-aliases-in-scipts'

* function-aliases-in-scipts:
  Use title-case for function aliases for consistency
  Create ‘changeSceneBackgroundTo()’ alias
  Make ‘Color’ an alias for ‘LNVL.Color’ in dialog scripts
  Alias LNVL.Scene.changeTo() to the function changeToScene()
  Allow function aliases in dialog scripts
  Clarify that CreateConstructorAlias() makes a ‘constructor alias’