Remove commons-collections; Replace FastHashMap with ConcurrentHashMap

[chrismaeda]

We needed to eliminate commons-collections 3 for a large corp. due to security concerns.

This replaces FastHashMap with ConcurrentHashMap and removes commons-collections.

FYI We also submitted a PR to commons-beanutils2 to modify that repo to be a commons-collections -free version that can replace beanutils 1.9.4.

[garydgregory]

-1 due to binary compatibility. Also the POM changes are invalid.

[arturobernalg]

HI @chrismaeda You can check if the change brake the binary by running japicmp:cmp Regards,