win: No longer support building with VS Express

The Community edition can provide everything we need for Professional
edition.

atom.gyp

@@ -932,31 +932,5 @@
         },  # target generate_node_lib
       ],
     }],  # OS==win
-    # Using Visual Studio Express.
-    ['msvs_express==1', {
-      'target_defaults': {
-        'defines!': [
-          '_SECURE_ATL',
-        ],
-        'msvs_settings': {
-          'VCLibrarianTool': {
-            'AdditionalLibraryDirectories': [
-              '<(atom_source_root)/external_binaries/atl/lib',
-            ],
-          },
-          'VCLinkerTool': {
-            'AdditionalLibraryDirectories': [
-              '<(atom_source_root)/external_binaries/atl/lib',
-            ],
-            'AdditionalDependencies': [
-              'atls.lib',
-            ],
-          },
-        },
-        'msvs_system_include_dirs': [
-          '<(atom_source_root)/external_binaries/atl/include',
-        ],
-      },
-    }],  # msvs_express==1
   ],
 }

common.gypi

@@ -6,11 +6,6 @@
       ['OS=="mac" or OS=="linux"', {
         'clang': 1,
       }],
-      ['OS=="win" and (MSVS_VERSION=="2013e" or MSVS_VERSION=="2012e" or MSVS_VERSION=="2010e")', {
-        'msvs_express': 1,
-      },{
-        'msvs_express': 0,
-      }],
     ],
     # Required by breakpad.
     'os_bsd': 0,

script/update-external-binaries.py

@@ -28,7 +28,6 @@ def main():
     download_and_unzip('ReactiveCocoa')
     download_and_unzip('Squirrel')
   elif sys.platform in ['cygwin', 'win32']:
-    download_and_unzip('atl')
     download_and_unzip('directxsdk')
     download_and_unzip('vs2012_crt')