Putting ("-") in dart script file name breaks dart2js compilation.

[eobodo]

This bug is easily reproduce-able by creating a test project, then renaming the dart script to include a ("-"). Tested in AngularDart 0.10.0 using pub build. Error log is posted below:

--- 3:24:30 AM Running pub build ... ---
Pub build failed, [65] Loading source assets... (1.4s)
Loading di transformers... (5.3s)
Loading angular transformers... (2.5s)
Building test2... (12.6s)
[Warning from Dart2JS]:
This transformer didn't emit declared output assets test2|web/test-2_static_injector.dart.js, test2|web/test-2_static_injector.dart.precompiled.js and test2|web/test-2_static_injector.dart.js.map.
[Info from Dart2JS]:
Compiling test2|web/test-2_static_expressions.dart...
[Error from Dart2JS]:
web\test-2_static_expressions.dart:1:23:
Expected ';', but got '-'.
library test2.web.test-2.generated_expressions;
^
[Info from Dart2JS]:
Took 0:00:01.628000 to compile test2|web/test-2_static_expressions.dart.
[Info from Dart2JS]:
Compiling test2|web/test-2.dart...
[Error from Dart2JS on test2|web/test-2.dart]:
web\test-2_static_expressions.dart:1:23:
Expected ';', but got '-'.
library test2.web.test-2.generated_expressions;
^
[Info from Dart2JS]:
Took 0:00:01.509000 to compile test2|web/test-2.dart.
[Info from Dart2JS]:
Compiling test2|web/test-2_static_metadata.dart...
[Error from Dart2JS]:
web\test-2_static_metadata.dart:1:23:
Expected ';', but got '-'.
library test2.web.test-2.generated_metadata;
^
[Info from Dart2JS]:
Took 0:00:00.431000 to compile test2|web/test-2_static_metadata.dart.
Build failed.