peer: fix memory alignment for integers used atomically on 32-bit archs
peer: fix memory alignment for integers used atomically on 32-bit archs

This commit fixes a panic that can occur on 32-bit systems to the
misalignment of a int64/uint64 that’s used atomically using the atomic
package. To fix this issue, we now move all int64/unit64 variables that
are used atomically to the top of the struct in order to ensure
alignment.

Cleaning up some dead-code, satoshisSent/satoshisReceived have been
removed as they aren’t currently used. Instead those values are
accessed directly from the channel themselves.

ddustin/lnd,LightningNetwork/lnd,LightningNetwork/lnd,ddustin/lnd,AndrewSamokhvalov/lnd,AndrewSamokhvalov/lnd,aakselrod/lnd,aakselrod/lnd