[PATCH 01/14] Add minimal binary heap implementation

Will be replaces by the "binaryheap.[ch]" from Abhijit once its been reviewed.
---
 src/backend/lib/Makefile     |   3 +-
 src/backend/lib/simpleheap.c | 255 +++++++++++++++++++++++++++++++++++++++++++
 src/include/lib/simpleheap.h |  91 +++++++++++++++
 3 files changed, 348 insertions(+), 1 deletion(-)
 create mode 100644 src/backend/lib/simpleheap.c
 create mode 100644 src/include/lib/simpleheap.h