Add the HTML5 "step" attribute to the inputs in the send form, so that the new version of chrome will actually let us send reasonable amounts of BTC as our fees.
Added steps to the buy and sale forms, so that the new version of chrome will let us enter floats.
Remove the step on the # of blocks, since those really can't be fractional.
Merge pull request #366 from curtislacy/Input-Steps-On-All

Add "step" attribute to fee and amount fields.