Unwanted trailing slash added to basePath (addTrailingS3Sep should be optional ?)

[ftrudeau]

Current usage

basePath set to commit hash, which is intended to be the base directory in S3.
Ex: Set basePath to de40ad249, so that every assets are uploaded into that directory

Current behavior

basePath: de40ad249
Resulting basePath: de40ad249/
Resulting Key: de40ad249//assets/scripts/vendor.js

Note the additional trailing slash automatically appended by the tool, which is effectively creating an empty directory in S3.

Desired behavior

basePath: de40ad249
Resulting basePath: de40ad249
Resulting Key: de40ad249/assets/scripts/vendor.js