Addin improvements and more

• More overrides for Where and WhereList
• Addin: Support for omitting a column from Update/Insert using the NOSAVE keyword
• Addin: Support for omitting the Collection class
• Addin: All keywords are now case-insensitive
• Addin: Macro documentation is now in Markdown, nicely formatted when read on GitHub
• Some minor refactoring
• Major refactoring in Addin's code