Update .gitignore
Add generic type arguments, formatting
Remove line comment with obsolete static field
Don’t mask ASDU of length 0
Restructure message representation of toString
Update textual representations of APCI and TPCI

Use underscore separator for layer prefix, start control information 
with uppercase.
Remove unnecessary casts
Merge branch 'master' into feat/jse-embd8-c1
Use Throwable argument in KNXException
Replace LogService.fatal with LogService.error

slf4j does not provide a method for level fatal.
Comment out LogService.fatal, as that method is removed
Add generic log method with log level, comment out LogService.fatal
Add getSlf4jLogger as wrapper for logger creation
Replace Calimero LogService with slf4j Logger

Use generic LogService.log where necessary, and update the 
enabled-checks for the log level before logging the message.
Merge branch 'feat/jse-embd8-c1' into feat/slf4j