add a trace method, to monitor step by step
add Flag state shown to console.

After call "trace p5" method, the "T" or "F" shown above
is to intend whether corresponding column needs to be calculated
in next step.
add a timing method
add time cost to each test case
Merge branch 'iotrace'
improve the intpartition algorithm

Time complexity reduces from O(n^m) to O(C(n+1, m)),
it is the minimal time cost, because it is the length of result.
refresh the time cost for test cases, 10+ times faster for some cases

Compare to previous, it saves more time when n,m is both large.
Merge branch 'alg-improve'