2.4.15 remove sigchain from build

2.4.14

- Use latest cargo-web in Makefile

2.4.13

- Fix android push notification priority to wake idle devices

- fix Go1.11 build

2.4.11 - Upgrade error_chain to fix warnings

2.4.10 - krd stability improvements, macOS 10.14

- Fix krd lifecycle when multiple users on the same machine are running
krd in parallel
- Use IdentityAgent SSH config directive when supported (workaround for
macOS 10.14 incompatibility with PKCS11 module)
- Fix macOS 10.14 reattach-to-user-namespace warning handling

2.4.9 - krd stability improvements

- Fix krd lifecycle when multiple users on the same machine are running
krd in parallel
- Use IdentityAgent SSH config directive when supported (workaround for
macOS 10.14 incompatibility with PKCS11 module)

- Reject proxy urls with invalid scheme

- Improve proxy URL handling

- Ignore empty http_proxy env vars