Partial fix for compound assignments, meaning that it now at least compiles.
Partial fix for compound assignments, meaning that it now at least compiles.

hjwylde/whiley-compiler,hjwylde/whiley-compiler,Whiley/WhileyCompiler,hjwylde/whiley-compiler,hjwylde/whiley-compiler,hjwylde/whiley-compiler