Added crop parameter support

[eoutvik]

wp_get_attachment_image_src($attachment_id, array(300,300, true));

Will return the same as:

wp_get_attachment_image_src($attachment_id, array(300,300));  

Additionally you can also set the crop parameter to false like this:

wp_get_attachment_image_src($attachment_id, array(300,300, false));

:+1:

[oherman]

After deliberation, this one's accepted. Thanks for your contribution.