Encode image filenames (#69)

Closes #68

Author: georgeh

server/wp-client.js

@@ -35,7 +35,7 @@ function makeMultipartBody( payload, boundary ) {
 body = body.concat(
 Utilities.newBlob(
 '--' + boundary + CRLF
-+ 'Content-Disposition: form-data; name="' + k + '"; filename="' + fileNameForBlob( v ) + '"' + CRLF
++ 'Content-Disposition: form-data; name="' + k + '"; filename="' + encodeURIComponent( fileNameForBlob( v ) ) + '"' + CRLF
 + 'Content-Type: ' + v.getContentType() + CRLF
 // + 'Content-Transfer-Encoding: base64' + CRLF
 + CRLF