Use strict date parsing when the input changes value

Found a bug where `2014--01` would convert to `2014-01-01` which made the input pretty much unusable, so I decided to turn on strict parsing. The date is now only selected if the date strictly matches `YYYY-MM-DD`
Merge pull request #25 from Hacker0x01/use-strict-parsing

Use strict date parsing when the input changes value