walk_tree->eval_tree, and broken up finally.
walk_tree->eval_tree, and broken up finally.

This makes walk_tree into a function that mostly calls other functions, and
no longer tries to do call stuff entirely inline. This greatly simplifies it,
and having 1 function per tree type (mostly), makes things saner.

Functions that walk trees are now considered to eval them instead, and have
eval in their name instead of walk. Also did some function location movement,
so that eval_build_list is next to the helpers it uses, and
try_find_storage_for_sig is now next to storage_for_class since they're
similar.

jesserayadkins/lily,jesserayadkins/lily,FascinatedBox/lily,FascinatedBox/lily,FascinatedBox/lily,FascinatedBox/lily,jesserayadkins/lily