Implemented more robust unicode handling.

* Immediatelly convert all args from `bytes` to `str`.
* Added `Environment.stdin_encoding` and `Environment.stdout_encoding`
* Allow unicode characters in HTTP headers and basic auth credentials
  by encoding them using UTF8 instead of latin1 (#212).

httpie/client.py

@@ -6,6 +6,7 @@ import requests
 
 from . import sessions
 from . import __version__
+from .compat import str
 from .plugins import plugin_manager
 
 
@@ -79,11 +80,18 @@ def get_requests_kwargs(args):
         if args.certkey:
             cert = (cert, args.certkey)
 
+    # This allows for unicode headers which is non-standard but practical.
+    # See: https://github.com/jkbr/httpie/issues/212
+    headers = dict(
+        (k.encode('utf8'), v.encode('utf8') if isinstance(v, str) else v)
+        for k, v in args.headers.items()
+    )
+
     kwargs = {
         'stream': True,
         'method': args.method.lower(),
         'url': args.url,
-        'headers': args.headers,
+        'headers': headers,
         'data': args.data,
         'verify': {
             'yes': True,