This task is spread out over several addons in release & contrib.

Purpose: To allow users to change which tabs the Addons appear in.

Fixes: It's a very common compliant that tabs get easily overcrowded & misused. This fixes that by allowing users to set up their own tab system or relocate addons to where they need them within the toolshelf.

Usage: Open Addons Preferences, Rename the current Tab name to one you choose or leave as default.

Code:
Using Align Tools in contrib as an example

## Addons Preferences Update Panel
def update_panel(self, context):
    try:
        bpy.utils.unregister_class(AlignUi)
    except:
        pass
    AlignUi.bl_category = context.user_preferences.addons[__name__].preferences.category
    bpy.utils.register_class(AlignUi)   
    
class AddonPreferences(bpy.types.AddonPreferences):
    # this must match the addon name, use '__package__'
    # when defining this in a submodule of a python package.
    bl_idname = __name__

    category = bpy.props.StringProperty(
            name="Category",
            description="Choose a name for the category of the panel",
            default="Tools",
            update=update_panel)

    def draw(self, context):

        layout = self.layout
        row = layout.row()
        col = row.column()
        col.label(text="Category:")
        col.prop(self, "category", text="")

Addons Affected:
Note:`Defaults will not change
Addons Contrib (in Testing Category):
space_view3d_align_tools *Completed
space_view3d_toolshelf_menu *Completed
object_boolean_tools *Completed
oscurart_tools *Completed

Contrib I/O:`
Note:`Whilst Defaults will not change per se, it seems like i/o addons could be changed to a category Import/Export
i/o cacharanth *fix registration bug, no other change
i/o export paper model *no change
i/o mesh cache tools *no change

Addons Affected:
Addons Release (in Community Category):
space_view3d_3d_navigation *requires own Task
ui_layer_manager * Complete

Release I/O:`
io_import_scene_unreal_psa_psk ( still uses Misc Tab, will change to Import/Export ) *Complete
io_export_unreal_psk_psa ( still uses Misc Tab, will change to Import/Export ) *Complete
io_online_sketchfab *no change
light_field_tools ( still uses Misc Tab, will change to Tools Tab ) *Complete

Summary: This set's a positive trend in addons ui management, With the exception of the i/o tools I will be updating all the listed addons to include this function. Also misc category should not be used the three affected addons will have tab change as indicated above.

Thanks.