Also, removed the one from modules/python/src2/cv.py and cleared its
executable bit, since it's not a script.

Legend for new column is:
* FASTER - strong speedup
* faster - spedup is detected but it is unreliable
* <empty> - no change in speed
* slower - slowdown is detected but it is unreliable
* SLOWER - strong slowdown

This option provides an easy way to identify tests having no regression data
for sanity checks

* use OPENCV_TEMP_PATH environment variable on all platforms
* fix cleanup after OpenCV tests on Windows
* add --list flag to output names of all tests found
* do not override user-passed --perf_min_samples and --perf_force_samples
  options by --check flag
* fix complier checks inside run.py

* do not lose auto-selected device while running several tests
* reduce output noise
* list available devices if unable to auto-select device
* fix error message when no devices connected

Minor improvements: reduced verbosity of positioning tests; run.py - filter out non-executables on windows

Changed compiler flags for 32-bit MSVC;
Fixed handling of "d" suffix of debug binaries in run.py.