build(pubspec): Clean up pubspec files

Add a direct dependency on package:path.
Remove dependency on package:quiver

modules/angular2/pubspec.yaml

@@ -17,6 +17,7 @@ dependencies:
   intl: '^0.12.4'
   logging: '>=0.9.0 <0.12.0'
   observe: '^0.13.1'
+  path: '^1.0.0'
   protobuf: '^0.5.0'
   source_span: '^1.0.0'
   stack_trace: '^1.1.1'

modules_dart/transform/pubspec.yaml

@@ -1,7 +1,7 @@
 name: ng2_transform
 version: 0.0.0
 environment:
-  sdk: '>=1.8.0 <2.0.0'
+  sdk: '>=1.10.0 <2.0.0'
 dependencies:
   angular2:
     path: ../../dist/dart/angular2
@@ -13,11 +13,12 @@ dependencies:
   intl: '^0.12.4'
   logging: '>=0.9.0 <0.12.0'
   observe: '^0.13.1'
+  path: '^1.0.0'
   protobuf: '^0.5.0'
-  quiver: '^0.21.4'
   source_span: '^1.0.0'
   stack_trace: '^1.1.1'
 dev_dependencies:
   transformer_test: '^0.2.0'
   guinness: any
+  quiver: '^0.21.4'
   test: '>=0.12.0 <0.13.0'