In package mingw-w64-x86_64-icu, version 58.2-3, the names of static
library files were changed, which leads to changes in CMakeLists.txt as
needed for compiling for Windows.
Deleted 3 out of 4 calls to method connection_basic::sleep_before_packet
that were erroneous / superfluous, which enabled the elimination of a
"fudge" factor of 2.1 in connection_basic::set_rate_up_limit;
also ended the multiplying of limit values and numbers of bytes
transferred by 1024 before handing them over to the global throttle
objects
rbrunner7