v2.5.1

Changes:

• new devspace add service/image functionality (see #432)
• better detection of changes in docker context path by using crc32 instead of mtime/size
• new --service flag for devspace add port/sync commands
• rephrased log messages if devspace.terminal.disabled is true

Fixes:

• fixed nil pointer if .kube/config does not have a current kube context (#408)