Escape arguments coming from Ruby scripts

[kylehowells]

The Ruby scripts did not work for my when I was trying the face detection example. I was doing a few things wrong, but eventually I got it to work. But only with files that didn't have spaces in the file path.

This commit escapes all the arguments being executed by the ruby scripts. Among other issues (safety) this also allows you pass the scripts images with spaces in their file paths.

http://ruby-doc.org/stdlib-2.0.0/libdoc/shellwords/rdoc/Shellwords.html

[kylehowells]

Hi, this patch allows the ruby scripts to be used on file paths with spaces in them. If there's a problem please let me know and I'll try to correct them.

[liuliu]

Thank you. Will squash merge to unstable branch shortly after.