Always show tags as a space-separated list to avoid confusion
Allow multiple tags in (filter by tag) on details page

* Modified filter to check if a document matches any of the tags
Improve UI for details section

* Added opacity to make it more obvious which record the user is hovering
  on
* Fixed styling for lines with too many tags
Lighten body text color
Allow user to enter a different currency

* Allows values that include currencies (such as '10 INR')
* Fixes bug (supposedly in Chrome) that wasn't allowing non-integer values
  without `step="any"` attribute
* Add short list of currency symbols to show symbols for currencies that
  have them (defaults to three-letter currency code)
Allow user to delete expenditure entries

* Changed UI for Save/Close/Delete buttons since it was getting too
  cramped
* Changed order of inline edit input boxes to be consistent with display
  order
Hide details of each day by default

* Added jquery explicitly (Spark includes this as a dependency). Swap for
  a smaller library later
Prevent NaN/null being saved as the value for an expenditure document

NOTE: Add proper data sanity checks, this is just temporary