Update README.md
Copy slugignore and .git clearing implementation from slug-compiler.
Wrap conditionals in quotes.
Message for slugignore deletion.
Don't nest git-ls-files conditional.
Add -c flag to git ls-files.
Roll back slugignore changes here too.
Fix potential to nuke all the things.

Happened to me D:
Merge pull request #21 from md-5/patch-1

Fix potential to nuke all the things.
Add Composer dependency installation
Tweak paths for Composer
More path tweaking
Try running PHP from build dir
More PHP path juggling
Run Composer in verbose mode
Unset git dir env var
Typo fix
Remove verbose option from Composer
Only run composer if vendors are not bundled
Typo fix