I will later split it into separate docs, for now just short notes.

VM_SECURITY_LEVEL - 0, 1 or 2
I had to choose between speed and safety in many places.
Security level 0 means that there are almost no checks.
Security level 1 means that only strictly run-time checks are performed,
like stack overflow check.
Security level 2 means that all checks are on, including stack items type
and required number control for all opcodes, check if we are not referencing 
not defined local variable etc.
For a long time we will work on security level 2, but it is designed in 
such way, that for perfectly generated asm file there is no possibilty of
security 2 violation. As we depend on correctness of asm file anyway (I
do not perform bytecode checks as java or Tatt's VM) we will be able to
move to security level 1 when reliable compiler is done.
It will be up to each implementor if he wants to move to security level 0
with considerable VM speedup (5-10% I think) but with cost in safety.
(It is reasonable choice if all programs were tested on level 1).

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How to add an opcode:
- add opcode def in vmopcodes.h
- add text to opcode entry in asmparser.cpp
- add case statement in vmrun.cpp
- add description to ../docs/vm/menmon.doc