CDB-2861 Fixed having to read into memory upload file to send it to AS3. For non-S3, forcing GC to clean the file
CDB-2861 Pending a big test finish, initially also downloading now is performed chunked. Also fix for broken specs (removed field apparently unused by mistake)
CDB-2861 added default values for filepath
Merge pull request #448 from CartoDB/CDB-2861

CDB-2861 Tested manually at staging with last commit fixes, no need for waiting to Travis