Identity v3 Projects List (#163)

* Identity v3 Projects List

* Rename ToListQuery to ToProjectListQuery
diff --git a/openstack/identity/v3/projects/results.go b/openstack/identity/v3/projects/results.go
new file mode 100644
index 0000000..33c70e1
--- /dev/null
+++ b/openstack/identity/v3/projects/results.go
@@ -0,0 +1,64 @@
+package projects
+
+import (
+	"github.com/gophercloud/gophercloud/pagination"
+)
+
+// Project is a base unit of ownership.
+type Project struct {
+	// IsDomain indicates whether the project is a domain.
+	IsDomain bool `json:"is_domain"`
+
+	// Description is the description of the project.
+	Description string `json:"description"`
+
+	// DomainID is the domain ID the project belongs to.
+	DomainID string `json:"domain_id"`
+
+	// Enabled is whether or not the project is enabled.
+	Enabled bool `json:"enabled"`
+
+	// ID is the unique ID of the project.
+	ID string `json:"id"`
+
+	// Name is the name of the project.
+	Name string `json:"name"`
+
+	// ParentID is the parent_id of the project.
+	ParentID string `json:"parent_id"`
+}
+
+// ProjectPage is a single page of Project results.
+type ProjectPage struct {
+	pagination.LinkedPageBase
+}
+
+// IsEmpty determines whether or not a page of Projects contains any results.
+func (r ProjectPage) IsEmpty() (bool, error) {
+	projects, err := ExtractProjects(r)
+	return len(projects) == 0, err
+}
+
+// NextPageURL extracts the "next" link from the links section of the result.
+func (r ProjectPage) NextPageURL() (string, error) {
+	var s struct {
+		Links struct {
+			Next     string `json:"next"`
+			Previous string `json:"previous"`
+		} `json:"links"`
+	}
+	err := r.ExtractInto(&s)
+	if err != nil {
+		return "", err
+	}
+	return s.Links.Next, err
+}
+
+// ExtractProjects returns a slice of Projects contained in a single page of results.
+func ExtractProjects(r pagination.Page) ([]Project, error) {
+	var s struct {
+		Projects []Project `json:"projects"`
+	}
+	err := (r.(ProjectPage)).ExtractInto(&s)
+	return s.Projects, err
+}