v0.5.0 Update

• Background 'string' drawer now extracted and made more use in other places in the package (namely the Theme main and header backgrounds).
• Helper methods in UIComponent and ParameterList are far more feature complete now. Can get/set parameter and style parameter values far more easily.
• Set the default version for new instances of the Host component to 2 as version 2 is far more feature rich and also fairly stable.
• ParameterList drawer is now foldable, meaning that the inspector doesn't get completely overwhelmed with all of the parameter properties drawing at all times.
• Parameter creation in code is far more friendly now, accepting parameterless constructors and typed constructors for the appropriate types the parameters box around.
• Can now construct states, parameter lists, etc. with object initializers and collection initializers, meaning that code-created elements can take up just a few lines of code now instead of lots of boilerplate-style code being required. The older construction methods are still 100% supported and backwards compatible alongside this new initializer interface.