Update generated index.coffee to use fs.existsSync

Script loading should be synchronous, to preserve script load order and
allow the script to behave as expected with the `--config-check` hubot
flag. Also ensure the scripts are loaded in alphabetical order. This
matches how hubot loads scripts from the scripts/ directory.
Merge pull request #19 from kballard/patch-1

Update generated index.coffee to use fs.existsSync
Add CHANGELOG for 0.2.1
speling
Merge pull request #21 from github/release-0.2.1

Prepare for 0.2.1 release
Merge remote-tracking branch 'upstream/master'