New heuristics for MCF algorithms (#340)
and some implementation improvements.

- A useful heuristic is added to NetworkSimplex to make the
initial pivots faster.
- A powerful global update heuristic is added to CostScaling
and the implementation is reworked with various improvements.
- Better relabeling in CostScaling to improve numerical stability
and make the code faster.
- A small improvement is made in CapacityScaling for better
delta computation.
- Add notes to the classes about the usage of vector<char> instead
of vector<bool> for efficiency reasons.

#!/bin/sh

# Run in valgrind, with leak checking enabled

valgrind -q --leak-check=full "$@" 2> .valgrind-log

# Save the test result

result="$?"

# Valgrind should generate no error messages

log_contents="`cat .valgrind-log`"

if [ "$log_contents" != "" ]; then

        cat .valgrind-log >&2

        result=1

fi

rm -f .valgrind-log

exit $result