Added abstraction for resources transformation.

Review: https://reviews.apache.org/r/29018
Added a Resources transformation for acquiring persistent disk.

Review: https://reviews.apache.org/r/29128
Fixed a compilation issue on gcc 4.4.7.
Removed an unnecessary helper in the sorter tests.

Review: https://reviews.apache.org/r/29088
Fixed the DRFSorter share calculation to not assume flattened resources.

Review: https://reviews.apache.org/r/29089
Add ReservationType and ReservationInfo for dynamic reservations.

Review: https://reviews.apache.org/r/28697
Modified Resources to account for reservation type.

Review: https://reviews.apache.org/r/28698
Update the C++ Scheduler API.
Add dynamic reservation information to LaunchTasksMessage.
Update the master and allocator + Added a test for acquiring dynamic reservations.