Add SIZE token to Campaign (PCC) files

SIZE Campaign (PCC) Token

This allows Size objects to be loaded from a PCC file rather than solely from the game mode

Usage:
SIZE:x|y

x is a file name
y is the Trailing include/exclude et al (as most other tokens in that file)

WARNING: Differences from Game Mode load:
In the Game Mode, a size can have multiple lines prefixed with SIZENAME

In the PCC file version, a size MUST be treated as any other file. Additional lines REQUIRE .MOD
Also, this means the prefix is dropped (since the PCC system knows the file contains SizeAdjustment objects)