Don't try to run the clone code if the directory already exists.
-rw-r--r-- 13 .gitattributes
-rw-r--r-- 71 .gitignore
-rw-r--r-- 15099 GPL-LICENSE.txt
-rw-r--r-- 1074 MIT-LICENSE.txt
-rw-r--r-- 1797 Makefile
-rw-r--r-- 2074 README.md
-rw-r--r-- 667 Rakefile
-rw-r--r-- 4790 build.xml
drwxr-xr-x - build
drwxr-xr-x - speed
drwxr-xr-x - src
drwxr-xr-x - test
-rw-r--r-- 6 version.txt