Bug fix

Eliminated errors sometimes occur during object deletion.
Feature Improvement: ElementsLocation validator

ElementsLocation property validator performs more detailed check of the
new location matrix
Bug fix

Fixed 2 bugs:
- Incorrect handling of H if its an hgwrapper array
- Ignoring delopt optional input argument
Misc improvements

- Documentation
- Removed redundancy between the function and the function it calls
- Introduced the use of validateattributes built-in functions
Feature improvement

Improved input argument checks
Bug fix

Child HG object handles need to be stored as handle objects (instead of
double) for proper behavior later on.
Bug fix: Visible Property

Visible property was not settable