[WIP] Begin Defining Type Signatures for Table Methods

[robertDurst]

While type checking is limited until we have a proper Table type, we can start defining the type signatures for Table methods now in order to allow more programs to type check. These checks will initially be pretty shallow/limited.

This directly addresses a few bug reports:

• Method not found when type checking Table stemming from incomplete set of methods in global provides #1693
• internal error on type check + tables #1662
• type-check internal error #1422

[shriram]

Oooh, exciting!