Merge branch 'smueller/eu_typemap' into blead

Merge branch 'smueller/eu_typemap' into blead

Much of ExtUtils::ParseXS was rewritten and cleaned up.
It has been made somewhat more extensible and now finally
uses strictures.

The logic for parsing, merging, and dumping XS typemaps was extracted
from ExtUtils::ParseXS into a module of its own, ExtUtils::Typemaps.
ExtUtils::Typemaps offers an interface to typemap handling outside of
the scope of the XS compiler itself.

As a first use case of the improved API an extensibility, typemaps can now
be included inline into XS code with a HEREDOC-like syntax:

  TYPEMAP: <<END_TYPEMAP
  MyType    T_IV
  END_TYPEMAP