Add a new isAws flag to enable aws v2 api.

Fix dir npe issues (merge request !3)

Add a partSize parameter.

Make ReadAhead related const into optional arguments.

v0.24.0

up it some more, looks like TestBenchLs can take more than 530s

what if we just give it more time?

print time if we get timeout

don't fail if we have account and key already

fix azure-storage-fuse build

update submodule to fix #483

log adl2 header values if we get InvalidHeaderValue

use 5 minutes limit

we often see travis timeout our tests because there's no output for

retry ourselves to workaround https://github.com/Azure/go-autorest/issues/470