Migrate development-dependencies to be managed by Cask.

This removes the final build-time warning and enables
us to setup error-as-warning for the build, as discussed in:

#81

Author: josteink

.travis.yml

@@ -29,4 +29,4 @@ matrix:
 
 script:
   - emacs --version
-  - make test
+  - cask exec make test

Cask

@@ -1,5 +1,9 @@
 (source gnu)
-(source melpa)
+(source melpa-stable)
 
-(files "*.el")
 (package-file "csharp-mode.el")
+(files "csharp-mode.el")
+
+(development
+ (depends-on "dash")
+ (depends-on "assess"))

csharp-mode-tests.el

@@ -21,20 +21,6 @@
 (require 'csharp-mode)
 (require 'package)
 
-;; development only packages, not declared as a package-dependency
-(package-initialize)
-(add-to-list 'package-archives '("melpa" . "https://stable.melpa.org/packages/"))
-
-;; required to resolve SEQ (or anything on elpa) on Emacs25.
-(setq package-check-signature nil)
-
-;; assess depends on dash 2.12.1, which is no longer available
-;; installing dash, resolves 2.13.0, and fixes this broken dependency.
-(dolist (p '(dash assess))
-  (when (not (package-installed-p p))
-    (package-refresh-contents)
-    (package-install p)))
-
 ;;; test-helper functions
 
 (defmacro assess-face-in-text= (testee &rest assessments)