* Speed up CIPLabeler
std::list is almost never the data structure that you want. vector
uses fewer allocations, and the data has better locality. This
speeds up the CIPLabeler on some protein examples by about 2x.
* Greg's recommendation to use std::vector
It's just as fast. For my example, this made queue sizes of like
1,186,390. Reserving ahead doesn't affect performance.
aa7d864612