Add multipart form support. Does not yet handle additional post parameters correctly.
Add support for OAuth-signed parameters when using multipart POST
Update tests to use multipart upload
Expand "~" to home path
Add file upload support to the commandline, using the same technique as openphoto-php
Merge branch 'multipart' into trovebox

Conflicts:
	openphoto/openphoto_http.py
	tests/test_base.py