NDF Excel : ensure all filled columns are visible

Here we refactor quite a bit the export module:

* we remove unnecessary code (previously tagged with FIXME)
* force telephonic fees visibility
* set a column visible if we set a width and it was previously hidden
Fix #73 : send email on expense status change
Ref #74 : Provide a getOneMonthAgo tool

It returns a JS Date object one month ago
Ref #74 : setDatePicker handle a new param today

Since we need to be able to set a default date adapted to the context,
we provide the ability to pass an optionnal "today" param to the
setDatePicker tool
Ref #78 : Tel expense popup enhancement

The tel expense popuped form didn't work has expected because no date
was provided.
Here :
we fix the date popup form by passing today as date for the default
model
we provide an appropriate default date for the expense popup
we fix the holliday elements update
Ref #74 : Provide a today options to the expense form

today is the first day of the month concerned by the current edited
expense sheet.