use sw::Ring instead
Move Register/DeRegister functions to SwNodeIndex

- allows more inlining
- allows removing another friendliness
- belongs there anyway

Change-Id: I5d0d24f60caa06533efcd3f41f313fe55dd365e1
Make SwNodeIndex constructors inline

Change-Id: Ib29bcd5e2028c4e644621af4294c193f5b0aa14e
remove Remove()

Change-Id: Ic1854d5e8cd76825290a3af94d8884e93dd7f0da
inline operator=

Change-Id: I2a74b9821072025cdf374d5e157411136e08ebec
inline Assign

Change-Id: Ibeb8d7b8e83d432a502707f83a8fde7900596aec
inline stream operator and remove object

Change-Id: I9df9a56eca662c6adf0a2cf4ef25a917da8dc609
c-style cast to const_cast

Change-Id: Ie5d8483305f4ef2d76c291fcb8c707a69ba9cf52
remove duplicated code

Change-Id: Id306d1dc75ef9d5ec5ec2e48be318e0632ea2377