add LowLockingMap and test code
update test case
add a chain hash table but it is non locking except rehash function
Revert "add a chain hash table but it is non locking except rehash function"

This reverts commit a6b45d52ebdffb72a2eac88d20db9a727b3d26d2.
Revert "update test case"

This reverts commit 34819357e17f4d3d58bd3604e6ee6abfa22870d1.
Revert "add LowLockingMap and test code"

This reverts commit 08b29a5e748316072db70fcc40927fc730d78ad0.
remove LowLockingMap
Revert "Add SumCount to count the number of elements"

This reverts commit 9a9822f2977d7e48ffd137e4bb167aeade869480.
Merge branch 'develop'