readlink on OS X is not the same as readlink on linux
Update per @RobSis feedback
Merge pull request #2 from unixorn/master

readlink on OS X is not the same as readlink on Linux :-(
Get the real parent directory of the script, even when running through
the symlink.
Fix typo in antigen instructions
Minor wording tweak
Merge pull request #5 from unixorn/master

README.md update
Zsh-powered script location resolution.
Fix name of file to source

Change 'zsh-syntax-highlighting.plugin.sh' to 'zsh-completion-generator.plugin.zsh'