Rewrite symbol/bindings system to avoid string usage

[austinzheng]

A very brief examination of the program's memory and CPU usage characteristics using the Instruments tool seems to indicate that the vast majority of resource usage is due to the inefficient way symbols and bindings are represented. Symbols and bindings should be interred, and the string names should only be used if the user requests them.

[austinzheng]

Pushed. Although there seems to still be a performance improvement (would need to do actual benchmarking to be certain), it should be noted that the incredibly bad memory and performance characteristics were primarily because of the debug build configuration.