Merge pull request #9 from mozillazg/master

add size param to control image size.
add overflow parameter to control how to resize image. #10
Add CASPERJS_CMD setting to bypass PATH lookup (ref #14)
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Merge pull request #13 from mozillazg/patch-2

Add overflow parameter to control how to resize image
Improve code layout
Rename overflow to crop
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Preparing release 0.2.0
Back to development: 0.3.0
Fixed crop feature code error
Merge pull request #15 from mozillazg/patch-3

Fixed crop feature code error (ref #13)
Return appropriate HTTP responses on parameter errors (400)
Move non-view stuff to utils
Save temporary file step is specified output is filepath
Better processing of capture errors, not remote for JS yet. (ref #1)
Mention screamshotter
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