add MAID class.
implement MAID.
Merge branch 'master' into MAID

Conflicts:
	src/jp/ac/titech/cs/de/ykstorage/service/Parameter.java
modify MAID.
remove unused imports and variables.
Merge branch 'master' into MAID
modify MAID.
implement LRU cache.
modify LRU cache.
Merge branch 'master' into MAID
modify constructor of MAIDDataDiskManager.
modify LRU cache.
add parameter for proposal.
Merge branch 'master' into MAID
modify Parameter for demo.
Merge branch 'master' into MAID
Merge branch 'master' into MAID
modify MAID client.
fix write through for MAID.
Merge branch 'master' into MAID

Conflicts:
	src/jp/ac/titech/cs/de/ykstorage/service/Parameter.java