Bone Roll Bugfixes (Ctrl R transform mode):

* Now, when X-Mirror is turned on for the armature, the roll from bones being 'rolled' is also mirrored.
* Disabled transform-constraints for this mode, as it didn't really make sense.

source/blender/src/editarmature.c

@@ -2959,6 +2959,7 @@ void transform_armature_mirror_update(void)
 				}
 				if(ebo->flag & BONE_SELECTED) {
 					eboflip->dist= ebo->dist;
+					eboflip->roll= -ebo->roll;
 					eboflip->xwidth= ebo->xwidth;
 					eboflip->zwidth= ebo->zwidth;
 				}

source/blender/src/transform_generics.c

@@ -403,6 +403,7 @@ void initTransModeFlags(TransInfo *t, int mode)
 	case TFM_CREASE:
 	case TFM_BONE_ENVELOPE:
 	case TFM_CURVE_SHRINKFATTEN:
+	case TFM_BONE_ROLL:
 		t->flag |= T_NO_CONSTRAINT;
 		break;
 	}