Wait on `close` instead of `exit`.

If the version of Node.js is less than `0.7`, wait on a `"close"` event
from the ImageMagick process instead of `"exit"`. As of `0.7`, the
`exit` "fires when the child actually exits, `close` fires when all
stdio streams have closed."

See:

https://groups.google.com/forum/#!topic/nodejs/agsTbL-fco0/discussion
crop now supports srcData as well as srcPath
allowed no dstPath, because you might want stdout
Update imagemagick.js

While loop should check list length, otherwise you get an undefined. Return prop instead of props[0]
Enabling gravity to be specified as an option
Merge pull request #47 from bigeasy/child-close

Wait on `close` instead of `exit`.
Merge pull request #49 from jteplitz602/master

Made a few changes so that you don't have to write to file for cropping
Merge pull request #54 from pbrumm/master

I enabled gravity to be specified.
Got rid of long gone sys module dependency as well as adding test matter and did some long overdue clean up
missing var declaration
Merge pull request #53 from seanmcgary/patch-1

Update imagemagick.js
[readme] js code blocks use gh-style markup to enable syntax highlighting
[readme] Fixed typo in code example
parseIdentify() skips empty lines and lines containing only whitespace.
Merge pull request #62 from nuarhu/master

parseIdentify() : skip also lines containing only whitespace
Increase maxBuffer to 15MB for long animated GIF support