Release v1.4

**New**

* Added watermark support to `Signature::EntityFields` and `Signature::Form`
* Added signature and initials data support to `Signature`
* Added `Signature::Envelope#is_demo`
* Added `:scheduled` status for `Envelope`
* Added `Envelope#delegate_recipient!`
* Added `Envelope#signed_document!`
* Added `Signature::FieldMethods#assign_field!` support in templates and envelopes
* Added `Signature::Contact#add_integration!`
* `Signature::Form` now supports document methods
* `Signature::Form` now supports field methods

**Changes**

* Fixed `#owner_should_sign` and `#ordered_signature` in `Signature::EntityFields` as API now return boolean values
* Fixed `Signature::Role#can*` methods as API now return boolean values
* `Signature::Field#acceptable_values` should properly handle arrays
* `Signature::Form#fields_in_final_file_name` should properly handle arrays
* `Signature::DocumentMethods#documents!` now find documents both by `:documentId` and `:id`
* `Signature::Form#create!` now can be created without template