Revert "added file with helper class impl" -- will use Simon's approach instead

This reverts commit dfea61918b3e188313d4eefe529ddda76cba0694.
Better use Simon's approach:
Revert "added cross-platform timer helper functions for ms sleeps; in logging, use seconds only for display due to trouble with reading ms precision timers over multiple platforms (a regression, but can be improved again in the future if needed)"

This reverts commit a59c1153681712e1014a3eb2a618a8af98a38fb9.
USB interface: Only try to detach DTBs under *nix, not Windows.
usleep for *nix and Sleep() for Windows.
Make logging NowTime() Windows compatible.
Remove double include, copy-paste mistake...
removed overly verbose message
removed check for libusb lib on windows (if using FTD2XX) since requirement has been removed in 1f7ba438bf13d548222c3b59c849da692f34801f ; reflected this in the doc
added define to handle __func__ in MSVC