add empty classes for raposda storage manager
add attribute ownerDiskId to Block.

Also modified its unit test code.
fixed spell miss.
add a number of buffers configuration into Parameter.
removed unused class
add a module that assigns the buffer id to specified block id.
add buffer region object and its unit test code.
update YKStorageTestSuite
add RAPoSDABufferManager and its unit test code.
changed log message.
add some items of Parameter
add data placement policy module.
add replication policy module
add extracting buffer blocks in specified buffer region.
add some buffer operation methods
implemented RAPoSDA storage manager.

It do not run the unit test yet.
create empty RAPoSDA data disk manager
Bug fix. To update the watchdog starter switch.
Add a timestamp of the beginning of the standby state to DiskState class.
Implemented RAPoSDA data disk manager