Add DebugBreak() function for debugging purpose.
Fix wrong exception register assignment.

We should place frame entrance code before we set the exception register.
Proper compiling error handling using exceptions.

Compiler errors no longer generates "Exception uncaught". Most exceptions
are handled now and will output a proper error message including error
cause and line number.

Currently parser errors are minimalistic, but is okay at this time.

Note: ToScalar() error is not properly handled, I need to think of a better way
of passing node::location to it.
Remove display of current file/class/method.

since we have proper error message now.