Sort calculation results of a historical discharge calculation based on their start date. Therefore, there are two new inner classes TimerangeItem and HistoricalTimerangeItem that wrap a W, Q, Timerange (and delta Q). WQTimerange and HistoricalWQTimerange now implement a sort() that return the results (TimerangeItem or HistoricalWQTimerangeItem) sorted by their start date.

# Set root logger level to DEBUG and its only appender to A1.
log4j.rootLogger=DEBUG, A1
log4j.category.org.hibernate=DEBUG

# A1 is set to be a ConsoleAppender.
log4j.appender.A1=org.apache.log4j.ConsoleAppender

# A1 uses PatternLayout.
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%d - %m%n