Handle Windows command not found error being different

Using cross-spawn on Windows will return returnCode=1 and use stderr
message when command is not found. However it is expected that an Error is
returned from spawn in that case and error.code is ENOENT. This commit
handles Windows explicitly by checking if it is Windows, for the
returnCode, and also if the error message is appropriate.

Example Windows command not found error message:
	'command' is not recognized as an internal or external command,
	operable program or batch file.

/cc #397

src/beautifiers/beautifier.coffee

@@ -251,10 +251,18 @@ module.exports = class Beautifier
             env: env
           }
           cmd = @spawn(exe, args, options)
-            .then(({returnCode, stdout, stderr}) ->
+            .then(({returnCode, stdout, stderr}) =>
+              @verbose('spawn result', returnCode, stdout, stderr)
               # If return code is not 0 then error occured
               if not ignoreReturnCode and returnCode isnt 0
-                reject(stderr)
+                err = new Error(stderr)
+                windowsProgramNotFoundMsg = 'is not recognized as an \
+                internal or external command'#, operable program or batch file.'
+                @verbose(stderr, windowsProgramNotFoundMsg)
+                if @isWindows and returnCode is 1 and \
+                stderr.indexOf(windowsProgramNotFoundMsg) isnt -1
+                  err = @commandNotFoundError(exeName, help)
+                reject(err)
               else
                 resolve(stdout)
             )