Updated and fixed the types

[linusbrolin]

• Fixed exports so the library works properly in typescript projects.
• Fixed "Data" type, so it now properly has a typed "options" field, with the new added "RowOptions" interface, which was missing before.
• Moved "separation" from where it was wrongly listed in "DataOptions" to "RowOptions" where it belongs.
• Added missing "color" in "DataOptions" and made "fontSize" and "fontFamily" optional.
• Changed the type of "row" in header.renderer from the wrong "number" type to the correct "Data" type.
• Changed the type of "padding" in "Options" from the wrong "number[]" type to the correct "number | number[]" type.
• Added "addBackground" function, because it needs to be reachable in typescript projects.
• Added missing "callback" parameter in the "table" function.