. The VM stacks for passing function arguments and syntaticaly nested calls were...

. The VM stacks for passing function arguments and syntaticaly nested calls were merged into a single stack. The stack size needed for op_array execution is calculated at compile time and preallocated at once. As result all the stack push operatins don't require checks for stack overflow any more.
. Generators implementation was improved using the new VM stack. Now it's a bit more clear and faster.