added statistics message for client
added initial code for getting distinct values count inside of the executor
introduced piggyback folder and files
print number of distinct values on client side
updated util files
added files in piggyback
added launch-files to .gitignore
Merge branch 'executor_spike' of https://github.com/mpws2013n1/postgres into executor_spike

Conflicts:
	util/ALL.launch
	util/bringemup.launch
	util/killemall.launch
Merge branch 'executor_spike' of https://github.com/mpws2013n1/postgres
into interface_extension

Conflicts:
	src/interfaces/libpq/fe-protocol3.c
added PGStatistics struct to PGResult
PGStatistics contains PGColumnStatistics
conn->result->statistics->columnStatistics contains the number of
distinct values for each column
added table header manipulation
added includes to print.h and libpq-int.h
print real distinct values in table header
Add minimal value to columnStatistics
Add numerical identifier to column statistics
Add maximum value to numerical column statistics
changed hashset implementation for counting distinct values
Merge branch 'interface_extension' of https://github.com/mpws2013n1/postgres into interface_extension

Conflicts:
	src/backend/executor/execProcnode.c
	src/backend/piggyback/piggyback.c
fixed bug with loop variables
Merge branch 'interface_extension' of https://github.com/mpws2013n1/postgres into interface_extension
Merge branch 'interface_extension' into piggyback_master