fixing MaidManagerServiceTest.BEH_RegistedPmid test
file path shall not be used as disk_root
make InitialiseDiskRoot throwing exception in case of error
Merge pull request #15 from maqi/MAID-185_ChunkStoreTest.BEH_Constructor

Maid 185 chunk store test.beh constructor
Allow network tests to fail gracefully if testnet is unavailable.
removing regeister / unregister pmid
Merge pull request #17 from mmoadeli/MAID-109_MaidManagerServiceTest.BEH_RegistedPmid

Maid 109 maid manager service test.beh registed pmid
Merge pull request #16 from Fraser999/MAID-197_fail_gracefully

Allow network tests to fail gracefully if testnet is unavailable.