Support list this week
Change dateParser's parse api
"from this year to next year" will set start date to start of the year
Fix "list 3 weeks after today" to set start date to start of the week and end date to end of the week
For "list this week" and "find 3 months from now", set to start and end of period for search and list
Merge branch 'master' of https://github.com/cs2103aug2014-w14-1j/main