Use BTreeMap instead of HashMap in brainfuck.rs
Use BTreeMap instead of HashMap in brainfuck.rs

HashMap uses a cryptographically sound hashing algorithm, and so is much slower than BTreeMap. On my system:

$ bash run.sh
Rust
ZYXWVUTSRQPONMLKJIHGFEDCBA
8.53s, 2.1Mb

$ bash run.sh
Rust
ZYXWVUTSRQPONMLKJIHGFEDCBA
4.30s, 2.2Mb

Karlheinzniebuhr/benchmarks,chalucha/benchmarks,Karlheinzniebuhr/benchmarks,Karlheinzniebuhr/benchmarks,chalucha/benchmarks,erickt/benchmarks,Karlheinzniebuhr/benchmarks,kostya/benchmarks,erickt/benchmarks,k-bx/benchmarks,kostya/benchmarks,Karlheinzniebuhr/benchmarks,k-bx/benchmarks,k-bx/benchmarks,Karlheinzniebuhr/benchmarks,kostya/benchmarks,kostya/benchmarks,chalucha/benchmarks,Karlheinzniebuhr/benchmarks,k-bx/benchmarks,erickt/benchmarks,kostya/benchmarks,k-bx/benchmarks,erickt/benchmarks,k-bx/benchmarks,chalucha/benchmarks,Karlheinzniebuhr/benchmarks,chalucha/benchmarks,erickt/benchmarks,chalucha/benchmarks,k-bx/benchmarks,chalucha/benchmarks,Karlheinzniebuhr/benchmarks,k-bx/benchmarks,kostya/benchmarks,erickt/benchmarks,kostya/benchmarks,Karlheinzniebuhr/benchmarks,erickt/benchmarks,k-bx/benchmarks,kostya/benchmarks,erickt/benchmarks,kostya/benchmarks,chalucha/benchmarks,kostya/benchmarks,erickt/benchmarks,kostya/benchmarks,erickt/benchmarks,chalucha/benchmarks,kostya/benchmarks,k-bx/benchmarks,erickt/benchmarks,k-bx/benchmarks,chalucha/benchmarks,kostya/benchmarks,erickt/benchmarks,chalucha/benchmarks,chalucha/benchmarks,kostya/benchmarks