force jedi.vim's fileencoding to utf-8

Hi,

jedi.vim's fileencoding is not set:
![not-utf8](https://f.cloud.github.com/assets/1317203/1111987/69271ec6-19c8-11e3-9259-b296f6003a8f.JPG)

So it reports an error when loading jedi.vim:
![no-utf8-error](https://f.cloud.github.com/assets/1317203/1111989/744b7540-19c8-11e3-9870-b8d64593ac16.JPG)

I believe it is caused by jedi.vim's Line235:
`'call_signature_escape': "'≡'",`

I converted jedi.vim's fileencoding to utf-8 and everything works. Could this be included in the main repository?