Upgrade syncthing to v1.13.1 and write logfile to disk

• This release is the last which is compatible with macOS 10.11 (see #148)
• Update syncthing to v1.13.1 which fixes switching bug from tech-ui theme
• Write syncthing logfile to disk, see README.md (fixes #93)
• Deprecate use of TravisCI as we already use build.syncthing.net
• Use new xcworkspace for building the project
• Correctly vendor Sparkle updater with Cocoapods (issue introduced in #142)

Upgrade syncthing to v1.13.0

• Update syncthing to v1.13.0 which adds support for M1 processor (universal binary)
• Update sparkle updater to 1.24 to support M1 processor

Upgrade syncthing to v1.12.1

This release updates the bundled syncthing from v1.12.0 to v1.12.1.

Upgrade syncthing to v1.12.0

This release updates the bundled syncthing from v1.11.1 to v1.12.0.

Upgrade syncthing to v1.11.1

This release updates the bundled syncthing from v1.10.0 to v1.11.1.

Upgrade syncthing to v1.10.0

This release updates the bundled syncthing from v1.9.0 to v1.10.0.

Upgrade syncthing to v1.9.0

This release updates the bundled syncthing from v1.8.0 to v1.9.0.

Upgrade syncthing to v1.8.0

This release updates the bundled syncthing from v1.7.0 to v1.8.0.

Update syncthing to v1.7.0

!!NOTICE: A manual upgrade may be required due to versioning bug introduced in v1.6.1-1 and can be downloaded from github.com/syncthing/syncthing-macos

• Upgrade to syncthing daemon v1.7.0
• Only use bundled syncthing daemon
• Set STNOUPGRADE=true environment variable
• Remove old ~/Library/Application\ Support/Syncthing-macOS/syncthing from releases before v1.7.0
• Remove Advanced pane from Preferences
• Fixes bundle versioning typo once again (issue #120)

Update syncthing to v1.6.1

This bundles with the latest syncthing v1.6.1