This patch adds some minor improvements and fixes. Issue #12 has been resolved, so now Hebi uses .wav sound effects by default instead of .mp3. (You can still use .mp3 files in addition to .wav if you want to add custom sound effects.) PR #13 has been merged, fixing dirty exits on some Linux systems. PR #15 has been merged, adding support for HJKL and number pad movement input support. In additon, WASD input is now supported, totaling four movement schemes!