Complete tildes fix for python 2
Complete tildes fix for python 2

The fix #64 by @grahame was fixing the issue of sending tweets with
'~' for python 3 but not for python 2 due to urllib.urlencode's lack
of safe functions. Here's a dirty hack to do it anyway.
Any better fix welcome :)

tytek2012/twitter,adonoho/twitter,miragshin/twitter,Adai0808/twitter,hugovk/twitter,jessamynsmith/twitter,sixohsix/twitter