Added packaging and run/install scripts, based on sbt-native-packager

Using original scala start scripts instead of scripts generated
by sbt-native-packager.
Add installdir/etc to CLASSPATH in start-scripts

Many config files (e.g. Akka, Logback) are searched for in CLASSPATH,
installdir/etc (i.e. SCALA_HOME/etc) seems a good default place for them.
Fixed toString methods in prot.keithley.{Request, Command}
Changed prot.keithley.Request to not automatically end with "X" command
Changed KeithleyParser and SCPIParser apply() to return new parser
Improved and extended Keithley protocol implementation
Added Keithley487