add symlinks download
fix batch download after datamodel refactoring

use sha384 to check identical content

bugfixing
adding root checkbox to debug app

fix avatar handling and create schema
filter permissions for containers in handlers

use tempdir custom module instead of tempfile
fail with 400 when ObjectIds are not valid
check existing schemas against a list at startup
add json schema draft 4 specification
give a more detailed error message for keys mismatch
remove upload method in core.py = dependencies (util.upload_ticket +
json schema)
remove search call + method = schema

closes #27

handle files with a length that is an exact multiple of blocksize