Fix up directly nested unnamed structs (struct/struct, union/union)
Add "freebasic" to the dummy id
Rename FROG_DUMMYID -> DUMMYID_PREFIX
Try and handle typedef/tag id conflicts without silent mistakes
Automatically solve out array typedefs
Automatically solve out procedure typedefs
ast: Remove unused astNodeToNop()
ast: Really delete nodes instead of setting to NOP

Some checks don't check for NOPs and then have false-positives, e.g.
astCountCallConv(). Setting nodes to NOP is a cool trick, but to be correct
they really should be deleted.
ast: Remove ASTCLASS_NOP completely