save_power: Rename the script so that it is implementation independent.
save_power: Don't remove all USB 1.x modules unconditionally.
save_power: Add comments.
save_power: Try to save power for Intel wireless interfaces.
save_power: Set the interpreter to bash for more flexibility.
save_power: Set dirty_writeback to 15s.
save_power: Enable power saving for all kinds of devices.

This, in particular, also includes PCI and I2C devices, which were not
considered before.
save_power: Remove outdated knob for devices.
save_power: Add suggestions from powertop.
power_save: Minor refactoring for broader compatibility.
save_power: Mini-refactoring.