added 0.3 and nightly to travis; force Winston to use gtk

.travis.yml

@@ -4,9 +4,11 @@ os:
   - linux
   - osx
 julia:
+  - 0.3
   - 0.4
+  - nightly
 notifications:
-  email: false
+  email: true
 # uncomment the following lines to override the default test script
 script:
  - if [[ -a .git/shallow ]]; then git fetch --unshallow; fi

src/plotter.jl

@@ -143,8 +143,10 @@ function backend()
 
     elseif currentBackendSymbol == :winston
       try
+        @eval ENV["WINSTON_OUTPUT"] = "gtk"
         @eval import Winston, Gtk
         @eval export Winston, Gtk
+        #@eval Winston._winston_config.defaults["output_surface"] = "gtk"
       catch err
         error("Couldn't import Winston.  Install it with: Pkg.add(\"Winston\").\n   Error: ", err)
       end