Update for grunt@0.4.1

Hey there,

just came around looking for a better way to compress my images. I found your great addition but to bad it wasn't working out of the box. Since you are to busy atm to update it by yourself and there were just some minor fixes I thought I might do it :)

There you go. Updated and working again :)

Running "pngnq" task
>> Compressed 2 files
>> Uncompressed size: 8.27kb, Compressed size: 1.79kb, Savings: 78.34%

Running "pngmin" task
>> Compressed 2 files
>> Uncompressed size: 8.27kb, Compressed size: 0.16kb, Savings: 98.04%

Running "gifmin" task
>> Compressed 2 files
>> Uncompressed size: 0.88kb, Compressed size: 0.11kb, Savings: 87.07%

Running "jpgmin" task
>> Compressed 1 files
>> Uncompressed size: 554.13kb, Compressed size: 554.13kb, Savings: 0%

Running "inlineImg" task
>> Inlined: 1 Images in file: src/whoot.css

Running "sprites:icons36" (sprites) task
>> Generated image: src/icons36.png & CSS file: src/test.css

Done, without errors.