new elpa packages for ada-mode project related stuff

[Stephen Leake]

I'd like to create one or more new ELPA packages to support the ada-mode
project code.

The new files are:
    
env-project.el -- 70 lines
    Adds three new project defgenerics:
        project-refresh
        project-select
        project-deselect

    These should be in project.el in some future version of emacs.

    Then defines a project defstruct that declares/undeclares
environment variables when it is selected/deselected. ada-mode project
inherits this.

path-iterator.el -- 243 lines
    Provides an iterator for directory paths; returns one file at a
    time. Handles a mix of flat and recursive directories.
    Probably should be rewritten to use generator.el.

uniquify-files.el -- 687 lines
    Provides a completion style and completion table that presents
    uniquified file names to the user for completion.
    Uses path-iterator.el
    ada-mode project-file-completion-table uses this.

Ok to create these ELPA packages (in elpa/packages)?

-- 
-- Stephe