Merge pull request #8 from mapsherpa/master

Clarify README, update tasks to be async.
upload binary files as attachments

Uploading binary files was failing for me, the upload was not correctly
base64 encoding the asset nor was it uploading it as an attachment.
This fixes both issues for me on node 0.10, I believe it should work on
0.8 as well.
rename variables for sanity.
Merge pull request #11 from mapsherpa/patch-isBinaryFile

patching binary file uploads