plieser-EtE_encryption/tests: fixed bug in concurrent write
plieser-EtE_encryption/tests: added support for async write
plieser-EtE_encryption/tests: fixed compiler error in hash_tree_ad_test.cpp
plieser-EtE_encryption/tests: added support for Flush operation
plieser-EtE_encryption/tests: remove unnecessary async read/write calls
plieser-EtE_encryption/tests: fixed support for object cache