This commit introduces the `CustomRecords` type in the `lnwire` package,
designed to hold arbitrary byte slices. Each entry in this map can
associate with TLV type values that are greater than or equal to 65536.
The lnwire package implements the Lightning Network wire protocol.
This package has intentionally been designed so it can be used as a standalone
package for any projects needing to interface with lightning peers at the wire
protocol level.
Installation and Updating
$ go get -u github.com/lightningnetwork/lnd/lnwire