update format specific handling. (#502)

update format specific handling. (#502)

* update format specific handling.

Format specific allocate, copy, destroy functions use new/delete for
underlying data management.  Use brace intitializers for underlying
data.  Previous xmalloc/xcalloc and xfree were used.

Format specific copy functions use copy constructor of underlying data.

Format specific copy functions have a const source.

Format specific functions use static_cast instead of c-style casts.
This helps avoid casting away const accidentally.

When possible, assign the result of fs_chain_find to a const pointer.

Eliminate corruption of global lists by AN1 writer which was modifying
format specific data.  This also simplifies memomry management and
fixes a double delete.

Fix const correctness issues with an1 symbol lookup.

Correct an1 symbol lookup to avoid dependency on structure padding.

Catch make-an1sym.pl with an1sym.h.

* use reinterpret_cast w/ fs_chain_add fs_chain_find ...

instead of c-style casts.

* make format_specifc_data a base class

and the various flavors derived classes.

* use a QList for format_specific_data chains.

* split format specific defines ...

use reinterpret_cast to downcast format_specific_data.  dynamic_cast
is noticeably slower.

* add new formspec.h file.

* create FormatSpecificDataList class.

rename format specific related items.

* safety check for formspec nullptr function ptrs.

* replace format specific function pointers

with pure virtual clone function and dtor.