Doesn't start on the 10th

````
irb(main):026:0* ZeroFill.by_date(myDates, start_date: Date.parse("2013-07-10"))
=> {#<Date: 2013-07-29 ((2456503j,0s,0n),+0s,2299161j)>=>10, #<Date: 2013-07-30 ((2456504j,0s,0n),+0s,2299161j)>=>0, #<Date: 2013-07-31 ((2456505j,0s,0n),+0s,2299161j)>=>7, #<Date: 2013-08-01 ((2456506j,0s,0n),+0s,2299161j)>=>0, #<Date: 2013-08-02 ((2456507j,0s,0n),+0s,2299161j)>=>3}
````