Remove vendor directory.

The vendor directory should not be stored; users can just run composer
install.
Switch /admin/customers.json to /admin/custom_collections.json
Add missing parameters for custom collections.

See http://docs.shopify.com/api/customcollection for parameters.
Fixed definition for getProductImages.

The "id" parameter was missing, resulting in a 404.  This was added
using the same definition as getProductMetafields, although I'm not sure
that the type should be a string.

While fixing this I also corrected since_id and fields to be included in
the query not the uri.
Fix location of limit and page parameters.

These parameters are passed in the query not in the URI.  Other
parameters should also be corrected but this is left for issue #3.
Fix limit and page parameter location for collects.
Merge pull request #1 from elyobo/remove-vendor-directory

Remove vendor directory.
Merge pull request #2 from elyobo/correct-custom-collection-endpoint

Switch /admin/customers.json to /admin/custom_collections.json
Merge pull request #4 from elyobo/custom-collection-parameters

Add missing parameters for custom collections.
Merge pull request #6 from elyobo/fix-get-product-images

Fixed definition for getProductImages.
Merge pull request #7 from elyobo/fix-get-products-paging

Fix location of limit and page parameters.
Merge pull request #8 from elyobo/fix-collect-pagination

Fix limit and page parameter location for collects.
Fix for Issue #5. Updating postField to json.