CEP nodes can have cost 0 now; we break ties against unnecessary complements by testing for that case last

Cleaned up charset inlines in internal.h, with new charset_complement() and charset_restrict_to_range() support

ch_llvm JITs successfully, but its call to h_read_bits crashes; the HInputStream seems to be invalidated

fixing LLVM function declarations; turns out repeat calls to LLVMPointerType(...) create shadow declarations