[Pas2js] trunk changes

[Mattias Gaertner]

Hi,

Here are some recent changes to trunk pas2js:

option -Sj to allow/disallow typed const to be writable

option -M<modeswitch> to enable or disable a modeswitch, see option -im

option -im to show available modeswitches

typecasting unrelated classes now gives only a warning "Class types are
not related" instead of an error, Reason: FPC/Delphi compatibility

mode ObjFPC now checks procedural types in procedure arguments by
signature, reason: FPC compatibility. Note: FPC does that too in $mode
delphi, pas2js only in mode ObjFPC.

Mattias