supports multiple files upload using one form name

[fastcoding]

I updated a little to support multiple files using

<input type='file'  multiple name='one_name' />, 

after submit the form, lapis app will receive an array of { :filename, :content }. if multiple attribute is false, it works the original way.

The latest official version can only receive the last file by that input element name.

may I raise a pull request ?