Allow propagating to a list of items

Change-Id: I5ce3f1223d35fb91bb8568978b1ed97e8259696c
Document ensure_type definitions

Change-Id: I72c964490f755b9a54de244dfc4e90a2acf4565d
Propagate types through long expression nodes better

Specifically, allow making sure that the result is the right restriction of just integer or just float.

Change-Id: Iaf4054c2b0da0d45289c385287893f6fb13ff516
Improve handling of overloaded methods in XInvoke

Change-Id: Id88e02811f12192ade577e3b3262c1c2b242b571
Documentation for the type checking system

Change-Id: Id27671e679de4a8d943c37998fd01b37a3013f64
Fix some syntax and spelling errors in manual

Change-Id: I51176c3dd0d0c883b4bd0a6101f050db4d7bbcb6
Include extra XInvoke test

Change-Id: I1d9540d6703fa335ceb02d96818bb1206aee7cc2