Mergeall 3.0 comparison-phase variant speed tests (final).

Summary: 
    scandir() variant is 2X slower on Mac
    scandir() variant is no faster on Windows
    scandir() variant was formerly 1.5~2X faster in Windows
    Linux results are proportionately similar to Windows

Machine 1: Windows 7,      Sony Vaio Z, SSD,       2012 I7
Machine 2: Mac OS X 10.11, Macbook Pro, SSD,       2015 I5 (5th gen)
Machine 3: Ubuntu Linux,   Sony Vaio F, harddrive, 2010 I7

All tests were run:
-on Python 3.5
-on AC power
-after an initial run to neutralize caching impacts
-without logging to file or scrolling GUI comparison messages
-interleaved in time to negate system load impacts

All tests also use final mergeall 3.0 code with symlink support, 
cruft-file skipping, and code optimizations.  The non-scandir() 
final variant now uses stat() explicitly for type tests, making 
it faster on Windows than before (it was formerly 2X slower).
 

WINDOWS==================================================================

--See 3.0-mergeall-comparison-times-Windows.txt for final timings--

Compared    => files: 59800, folders: 4056
Differences => samefile: 0, uniqueto: 0, uniquefrom: 0, mixedmode: 0

non-scandir(), pre stat recoding
Phase runtime: 19.061627105722287     # and sometimes 16 or 20
Phase runtime: 15.371371951070515
Phase runtime: 15.431613568499811

scandir()
Phase runtime: 10.563905464248537     # and sometimes 11
Phase runtime: 10.485056274771406
Phase runtime: 10.537724866949139

non-scandir(), post stat recoding
Phase runtime: 10.367447133969632     # and sometimes 9.8
Phase runtime: 10.453071287893227
Phase runtime: 10.441923849458266

MAC======================================================================

Compared    => files: 59823, folders: 4051
Differences => samefile: 0, uniqueto: 0, uniquefrom: 0, mixedmode: 0

scandir()
Phase runtime: 9.016150443989318
Phase runtime: 9.092939175025094
Phase runtime: 9.013318493030965

non-scandir(), pre stat recoding
Phase runtime: 4.585963150020689
Phase runtime: 4.354359277989715
Phase runtime: 4.438925892987754

non-scandir(), post stat recoding
Phase runtime: 3.832143307023216
Phase runtime: 3.8482273359550163
Phase runtime: 3.755497715959791


# all are slightly faster when mergeall is run directly at the console with same 
# parameters, for causes unknown -- the launcher's stdout UTF8 encoding and/or 
# unbufferred mode?  direct run results on Mac follow:

# scandir()
$ py3 ../mergeall.py /MY-STUFF /MY-STUFF -skipcruft -report | grep 'Phase runtime'
Phase runtime: 8.779079572064802
$ py3 ../mergeall.py /MY-STUFF /MY-STUFF -skipcruft -report | grep 'Phase runtime'
Phase runtime: 8.64699007209856
$ py3 ../mergeall.py /MY-STUFF /MY-STUFF -skipcruft -report | grep 'Phase runtime'
Phase runtime: 8.717638614936732

# non-scandir() variant
$ py3 ../mergeall.py /MY-STUFF /MY-STUFF -skipcruft -report | grep 'Phase runtime'
Phase runtime: 3.5495357650797814
$ py3 ../mergeall.py /MY-STUFF /MY-STUFF -skipcruft -report | grep 'Phase runtime'
Phase runtime: 3.5263971380190924
$ py3 ../mergeall.py /MY-STUFF /MY-STUFF -skipcruft -report | grep 'Phase runtime'
Phase runtime: 3.5442208040039986


# verify same results of runs made in GUI launcher

$ diff ~/Desktop/test/mergeall-date170208-time142816.txt \
       ~/Desktop/test/mergeall-date170208-time142851.txt 
1d0
< Using Python 3.5+ os.scandir() optimized variant.
4059c4058
< Phase runtime: 9.032094128080644
---
> Phase runtime: 3.8343904009088874


LINUX====================================================================

Compared    => files: 59823, folders: 4051
Differences => samefile: 0, uniqueto: 0, uniquefrom: 0, mixedmode: 0