Switch from URI to Uri.

URI does not allow braces: {}, even though they are allowed in the spec.
It is also easier to build paths using a Uri instance.

Download/upload progress should be done with longs for large transfers.
Fix connection: close honoring
Merge branch 'master' of https://github.com/koush/AndroidAsync

# By Koushik Dutta
# Via Koushik Dutta
* 'master' of https://github.com/koush/AndroidAsync:
  Fix connection: close honoring
  Switch from URI to Uri.