New snapd release 2.25

Hello everyone,

The Snappy team is happy to announce the availability of snapd 2.25!

Some of the highlights:

• improved aliases implementation, details in https://forum.snapcraft.io/t/improving-the-aliases-implementation/18
• improved channels support (tracks), see https://forum.snapcraft.io/t/channels-2-0-implementation/156)
• per revision snapshots of the snap configuration
• refresh schedule support, see https://forum.snapcraft.io/t/refresh-schedule-via-core-config/434
• cross distro improvements (Xauthority handling, debian spread tests run automatically now)
• test improvements (more spread tests)
• more fine-grained seccomp support for ioctl and quotactl
• download robustness improvements (auto retry on hashsum and RST issues)
• add built-using header to the deb packages to make tracking revisions easier
• new snap tasks command
• speedup for device key generation on pi2,pi3
• run snap-confine from the core if snapd also runs from the core
• new interfaces: media-hub, kubernetes-support
• interface improvements