BCursor: add a constructor with bitmap and point

* enhancement #15169
* get_mouse_bitmap(): also reads the colorspace from app_server.
* docs and tests

Change-Id: Iba63f8a2789530ae596c30b92f14828f31761d98
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3292
Reviewed-by: Adrien Destugues <[email protected]>

docs/user/app/Cursor.dox

@@ -6,8 +6,8 @@
  *		John Scipione, [email protected]
  * 
  * Corresponds to:
- *		headers/os/app/Cursor.h	 hrev47355
- *		src/kits/app/Cursor.cpp	 hrev47355
+ *		headers/os/app/Cursor.h	 hrev54621
+ *		src/kits/app/Cursor.cpp	 hrev54621
  */
 
 
@@ -315,6 +315,18 @@
 */
 
 
+/*!
+	\fn BCursor::BCursor(const BBitmap* bitmap, const BPoint& hotspot)
+	\brief Initializes a new cursor object from a bitmap object and a point
+           object.
+
+	\param bitmap The bitmap object to initialize from.
+	\param hotspot The cursor hotspot.
+
+	\since Haiku R1
+*/
+
+
 /*!
 	\fn BCursor::~BCursor()
 	\brief Destroy the cursor and free its memory.
@@ -323,6 +335,17 @@
 */
 
 
+/*!
+	\fn status_t BCursor::InitCheck() const
+	\brief Returns the initialization status.
+
+	\return \c B_OK if the object was properly initialized or an error code
+	        otherwise.
+
+	\since Haiku R1
+*/
+
+
 /*!
 	\fn status_t BCursor::Archive(BMessage *into, bool deep) const
 	\brief Archive the cursor. Not implemented.