Creating parent collection method was added (#22)

* method for creating parent collection was added to Client struct

"func (c *Client) createParentCollection(itemPath string) error" was added to request.go file

* using Client's method to create parent collection

in following methods:
Client.Write()
Client.WriteStream()
Client.copymove()

deadlock is impossible in method Client.copymove() because of paragraph #6 section 9.8.5 (https://tools.ietf.org/html/rfc4918#section-9.8.5) and paragraph #6 section 9.9.4 (https://tools.ietf.org/html/rfc4918#section-9.9.4) of RFC 4918 (https://tools.ietf.org/html/rfc4918)

* install dependencies script was added to Travis-CI file

* testing was added to Travis-CI file

* error wrapping was removed from Client.put() method

* using an early return on error in case of 409 in Client.Write() method

client.go

@@ -346,13 +346,14 @@ func (c *Client) Write(path string, data []byte, _ os.FileMode) error {
 		return nil
 
 	case 409:
-		if i := strings.LastIndex(path, "/"); i > -1 {
-			if err := c.MkdirAll(path[0:i+1], 0755); err == nil {
-				s = c.put(path, bytes.NewReader(data))
-				if s == 200 || s == 201 || s == 204 {
-					return nil
-				}
-			}
+		err := c.createParentCollection(path)
+		if err != nil {
+			return err
+		}
+
+		s = c.put(path, bytes.NewReader(data))
+		if s == 200 || s == 201 || s == 204 {
+			return nil
 		}
 	}
 
@@ -361,8 +362,14 @@ func (c *Client) Write(path string, data []byte, _ os.FileMode) error {
 
 // WriteStream writes a stream
 func (c *Client) WriteStream(path string, stream io.Reader, _ os.FileMode) error {
-	// TODO check if parent collection exists
+
+	err := c.createParentCollection(path)
+	if err != nil {
+		return err
+	}
+
 	s := c.put(path, stream)
+
 	switch s {
 	case 200, 201, 204:
 		return nil