Generate Perl method bindings for every fresh method

This makes sure that methods overriding methods from another parcel will
always have bindings. Should fix test failures caused by missing
destructor bindings.

This increases the size of the Lucy bundle by about 2.6% on OS X 10.8.
Some of the size increase is due to method bindings we need anyway.
Generate default constructor XSub for every class
Remove unneeded binding code

It's not anymore necessary to create a CFCPerlClass just to generate
method and constructor XSubs.
Micro-benchmark for various types of method dispatch
Include parcel.h earlier in generated headers

Include parcel.h as soon as a parcel directive occurs in a .cfh file.
This should make C blocks at the top of a .cfh file work correctly.