The following changes have been made to the C++ codegen to enable writing generic code
that uses the Table and NativeTable types.
- Adds TableType and NativeTableType typedefs to NativeTable and Table structs.
- Adds GetFullyQualifiedName() to NativeTables if --gen-name-strings is set.
- Adds a static Pack function to Tables that simply calls the global CreateX functions.
See cr/140391505 as an example of improved usage.
From cl/140529288.
Change-Id: Idec137c16129e15c1783f94fabdcea24aeeaaef6