enable monitoring of ratios
refactored CloudWatchRatioMetric to use composition
small whitespace fix
make timespane editable
add summary for ratio metric
make timespane editable
add summary for ratio metric
added support for delta monitoring
Add period to delta metric, also force type=int
Merge pull request #3 from Jimdo/ratio_monitoring

Added ratio monitoring
Bumped version to 0.2.3 - Added support for ratio monitoring
Merge pull request #5 from Jimdo/delta_monitoring_fixed

Add support for delta monitoring
BugFix: include statistic period in time range for CloudWatchDeltaMetric
BugFix: bringing back da periodz
Bumped version to 0.2.4: Added support for delta monitoring