Search and delete tests

Wrote delete and search tests
Fixed search bug which prevented searching by date
Fixed bug in taskDateCompleted

Non-recurring tasks now also delete outdated dates. WARNING: Not able to
get deleted dates back
Merge branch 'daryl_storage'
Merge branch 'master' of https://github.com/cs2103aug2014-w14-1j/main into daryl-ui
Interface UIObserver
Comments on Task and TaskDate
Deleted Tests.java and replaced it with StorageTest.java. All tests have
been moved
Floating tasks return "" for date

Added appropriate test
SDF format for dates
Change UI Display to have only one date range.
Merge branch 'master' of https://github.com/cs2103aug2014-w14-1j/main into daryl-ui