Provide type from package

This prevents packages from needing instance of checks for package
class type

src/atom-package.coffee

@@ -24,6 +24,8 @@ class AtomPackage extends Package
   resolvedMainModulePath: false
   mainModule: null
 
+  getType: -> 'atom'
+
   load: ->
     try
       @metadata = Package.loadMetadata(@path)

src/text-mate-package.coffee

@@ -26,6 +26,8 @@ class TextMatePackage extends Package
     @scopedProperties = []
     @metadata = {@name}
 
+  getType: -> 'textmate'
+
   load: ({sync}={}) ->
     @metadata = Package.loadMetadata(@path, true)