Adds new-item button to view

Clicking on any project list elements sets the data-params property of
the button (a styled anchor) to the id of the project. (Clicking a non-
project entry like unsorted or favorites unsets the data param).

Also removes a lot of the logic that depends on Item#item_type, testing
for Item#image_file_name instead.
Makes "New Item" button work

When Item#new request is xhr, creates and saves a new item for the user,
then sends a json response of two partials (keyed by their jquery
variable names): one is the new item form, and the other is the item
list entry for the fresh item.

Those get appended to #itemContent and prepended to #itemList
respectively.
Removes references to item_type from validations
uses css calc() to get input widths
Deletes deprecated views/partials
Bootstraps tag names in main page
Increments count of items in a project on creation

Adds a helper function incrementCount which takes a jquery object,
finds the "small" element inside it, and increments its value by one.

Also ensures that the newly created item in the item list is selected
and not any previously selected item.
Reverse orders items so newst is on top
Item view pane starts in edit mode on creation
Adds item counts to non-project entries

Favorites, Unsorted, and Trashed have counts listed beside them.
Also adds styling to the counts, and headers inside the list.
Also starts the view pane in edit mode on item creation.
Adds route for trashed items, and trashing items

Also non-project categories in the project list now update their
item counts when an item is created.
Removes deprecated stylesheets.
Adds trash/untrash buttons and routes to match

Also auto-updates the Favorites counters in the project list each time
an item is favorited and unfavorited. The favorite and unfavorite
actions return json of action => "set" or "unset" depending on whether
or not it was favorited or unfavorited (a pattern that will be reused)
and the client accordingly removes the item from the item list if they
happen to be viewing the Favorites list at the time.
Control bar in header