Release v0.7.1

Improvements:

• Support Raspberry Pi
• Support multiple email recipients
• Add tag config option to identify schools
• Use system timezone in log file
• Allow editing most config options while running
• Support graceful shutdown via SIGTERM

Improvements specific to Eltern-Portal:

• Remove duplicate lines in substitution plan
• Support archived items in Schwarzes Brett
• Speed up reading of threads with teachers

Fixes:

• Decoding of %-encoded teacher names in Eltern-Portal