Reformat deft-new-file docstring
Use `file' instead of `filename' for consistency

This makes comparing deft-new-file and deft-new-file-named
easier.
Expand deft-directory for consistency

Expands tildes in `deft-directory' so that file
hashes have consistent keys.
Refactor and simplify new file functions
Ensure that newly created files get added
Make use of empty file string
Add C-o for opening files in another window

Used without a prefix argument (C-o), open the file in another window
without switching there.  When used with a prefix argument (C-u C-o),
switch to the new window.

Also included in this patch: check that newly opened buffers are not
already using `deft-text-mode' before switching to that mode.

Thanks to Juha Ranta <juharanta@me.com> for suggesting this feature.
Add after-save-hook to correct buffer
For symlinks, use modification time of target

Call file-truename before file-attributes.
When opening files, move point to first match

Includes a new function, `deft-filter-regexp-as-regexp' that
converts the filter string to a proper regular expression,
depending on which search mode is active.

When opening a file, search forward to the beginning of the
first match of the filter string.
Safely handle empty title or contents
Consistently use "regexp" instead of "regex"

This is in line with built-in Emacs commands and Emacs documentation.

NOTE: If you have been using the development version of Deft, and have
customized `deft-strip-title-regex', that variable has been changed to
`deft-strip-title-regexp'.
More coherent filter decrement behavior and better documentation

Fixes a minor bug where the colon in the "Deft:" prompt would remain
even after deleting all characters because `deft-filter-regexp' was
set to a list with an empty string, (""), rather than nil.
Add deft-filter-decrement-word (M-DEL)
Add deft-filter-yank (C-y)
Editing of filter string in minibuffer, with history (C-c C-l)
Catch invalid-regexp errors, use warning face in filter string
Leave point at end of match, like (re-)search-forward
Deft 0.5