Orange request; Bones in Armature now have own layer settings.

Works like for Object layers, but local within Armature itself. Each Bone
can be in (16 now) any layer, and the Armature layer defines what is
visible or not. Also note that hiding will still work too.

Since the Blender code is *stuffed* with Bone options now, this commit
requires a good test if all tools we got now comply to layers...
(I counted 130 cases for checking for selected Bones in code!)

In PoseMode; hotkey M will show 'movetolayer' menu. Not in editmode...
then its the mirror menu.

Todo: make action/nla drawing comply to Armature layer settings.

source/blender/python/api2_2x/Armature.c

@@ -453,7 +453,6 @@ static PyObject *Armature_saveChanges(BPy_Armature *self)
 		bone->rad_head= editbone->rad_head;
 		bone->rad_tail= editbone->rad_tail;
 		bone->segments= editbone->segments;
-		bone->boneclass = 0;
 	}
 
 	pos = 0;

source/blender/python/api2_2x/Bone.h

@@ -109,12 +109,11 @@ typedef struct {
 	PyObject_HEAD
 		//reference to data if bone is linked to an armature
 	Bone * bone;
-	//list of vars that define the boneclass
+	//list of vars that define the bone
 	char *name;
 	char *parent;
 	float roll;
 	int flag;
-	int boneclass;
 	float dist;
 	float weight;
 	VectorObject *head;