Better regexp to handle unified diff header

Author: Paulo Bu

src/diff-parser.js

@@ -152,10 +152,10 @@
       var values = [];
       if (utils.startsWith(line, 'diff')) {
         startFile();
-      } else if (currentFile && !currentFile.oldName && (values = /^--- a\/(\S+).*$/.exec(line))) {
+      } else if (currentFile && !currentFile.oldName && (values = /^--- [aiwco]\/(.+)$/.exec(line))) {
         currentFile.oldName = values[1];
         currentFile.language = getExtension(currentFile.oldName, currentFile.language);
-      } else if (currentFile && !currentFile.newName && (values = /^\+\+\+ [b]?\/(\S+).*$/.exec(line))) {
+      } else if (currentFile && !currentFile.newName && (values = /^\+\+\+ [biwco]?\/(.+)$/.exec(line))) {
         currentFile.newName = values[1];
         currentFile.language = getExtension(currentFile.newName, currentFile.language);
       } else if (currentFile && utils.startsWith(line, '@@')) {