inline_entity_form 7.x-1.0-beta2

Changes since 7.x-1.0-beta1:

• Add a README.
• #1527788 by bojanz: Add a form alter hook for the inline forms.
• Hide the cancel button if the reference field is required but contains no values.
• #1598296: Add a simplified widget for fields that accept only one entity of a specific type.
• #1489436: Clicking the main save button should save all inline entity forms.
• #1630508: Cannot read property 'disableFields' of undefined.
• #1527882: Handle deletion of non-deletable products.
• #1626706: Rework entity type specific code into controllers.
• #1621702: File upload doesn't happen on inline entity form submit.
• #1605400 by Amitaibu: Fixed Get correct bundle in inline_entity_form_field_attach_submit().
• #1559562: Fix errors when using IEF on an unsupported entity type.
• #1571370: Fix fatal error when cart module not enabled.
• #1572452 by joachim, bojanz: Simplify the type forms, cleanup code.
• #1528894 by wesleydv, bojanz: Support AutoSKU and do some cleanup.
• #1559544 by joachim: Fixed docblock and function disagree.
• Make sure the SKU and Title fields are always at the top.