Add optional argument for casting function in toJavaList()

- Add corresponding tests in TestToJavaList
- Implement input parsers to validate input
Move helper functions to src/ directory
Use inputParser in toMatrix() function
Move unit tests to test/unit folder
Delete deprecated demo/test functions
Remove deprecated helper functions
Remove references to gateway from loadOmero()
Fix build.xml to account for recent changes in OMERO.matlab

- Copy libraries in libs/ directory
- Copy src/ directory