Support date_text input

[jacobembree]

[NOTE: This is the same as #30 but without changes to date.js and date.min.js]

This allows a date input field to be a date_text instead of date_select. thus, all in one field rather than a bunch of date parts. There are four types of changes in this commit:

• Two checks for the widget type, date_text or date_select
• Moved the anonymous function that fills in the result into a named function so that it can be called outside of the loop if we don't need to loop (date_text)
• Indentation corrected in the changed blocks of code
• Renamed the date variable to d so as not to overwrite the date() function which gets used

[signalpoint]

@jacobembree Great pull request! That one added a lot (and abstracted a lot) for the project, thank you.