OBJ: Fix mistakes in rBAc03185fe40dc, add some tooltips.

Please do not commit random things to code maintained by other people,
especially if you are breaking basic 101 things like codestyle. This is
loss of time for everybody. Even worse since not ansewring to comments
on original commit.

Also no need to add extra `text` parameters (and more useless UI
messages) in add-ons, when the only usage of the property's name itself
is in own add-on' UI...

io_scene_obj/__init__.py

@@ -255,12 +255,12 @@ class OBJ_PT_export_include(bpy.types.Panel):
         sfile = context.space_data
         operator = sfile.active_operator
 
-        col = layout.column(heading = "Limit to")
+        col = layout.column(heading="Limit to")
         col.prop(operator, 'use_selection')
 
-        col = layout.column(heading = "Objects as", align = True)
-        col.prop(operator, 'use_blen_objects', text = "OBJ Objects")
-        col.prop(operator, 'group_by_object', text = "OBJ Groups")
+        col = layout.column(heading="Objects as", align=True)
+        col.prop(operator, 'use_blen_objects')
+        col.prop(operator, 'group_by_object')
         col.prop(operator, 'group_by_material')
 
         layout.separator()
@@ -421,18 +421,18 @@ class ExportOBJ(bpy.types.Operator, ExportHelper):
 
     # grouping group
     use_blen_objects: BoolProperty(
-            name="Objects as OBJ Objects",
-            description="",
+            name="OBJ Objects",
+            description="Export Blender objects as OBJ objects",
             default=True,
             )
     group_by_object: BoolProperty(
-            name="Objects as OBJ Groups ",
-            description="",
+            name="OBJ Groups",
+            description="Export Blender objects as OBJ groups",
             default=False,
             )
     group_by_material: BoolProperty(
             name="Material Groups",
-            description="",
+            description="Generate an OBJ group for each part of a geometry using a different material",
             default=False,
             )
     keep_vertex_order: BoolProperty(