Debugger: Detect whether the scope object and cell and free variables have been initialized for closures

fix decorator lookup by avoiding (re-)assignments to the function/class name before their execution (ticket #593)

Debugger: Recognition of module-level Cython code (initmodulename and PyInit_modulename)
Fix debug flag (import Parsing when needed)

Fix breakpoint approach for stepping (make stepping repeatable with breakpoints that are set and deleted instead of disabled)

Disable watchpoint stepping by default (use cy step -w or cy step --watchpoint to enable) as hardware watchpoints are limited.