osx: externalized the build shell script into a file, not as part of the project file.

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2461 86ba831e-150c-0410-ab35-e06eaae15ed9
osx: updated exepack.sh to support paths with spaces.

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2462 86ba831e-150c-0410-ab35-e06eaae15ed9
* Added some operator overloads to DLListItem so that a pointer to one behaves like a pointer-to-pointer to the item type it wraps. Very convenient syntax-wise.
* Added more safety to DLListItem<T>::remove, which has continued to prove itself an unstable factor during design of new systems. Cuts down on some boilerplate too.
* Added DLList class, that can be used to abstract out some logic of maintaining DLListItem-based lists.
* Somewhat useless but fun .pak-file based implementation of zone core dump. Helped me find out EE was still allocating an extra screens[] array though, so maybe not THAT useless.

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2463 86ba831e-150c-0410-ab35-e06eaae15ed9