v0.6.4 (hope)

New additions:

• Support for the Pyrmont testnet.

• The PCRE library is no longer needed to build Nimbus.

• Sensitive files such as keystores are now accessible only to the
  user of the beacon node on POSIX systems (the group rights have
  been dropped).

We've fixed:

• An issue preventing blocks from being downloaded when the client goes
  out of sync.

• Resource leaks that occasionally led to a reduction in network activity (caused by a build-up of malfunctioning peer connections).