Renamed T.cc files to T_impl.hh to get rid of IDE problems not showing them.

Status Job ID Name Coverage
  Test
passed #68036
VS2015
VS2015-32-bit

00:01:16

passed #68035
VS2015
VS2015-64-bit

00:01:21

passed #68034
VS2017
VS2017-32-bit

00:01:19

passed #68033
VS2015
VS2017-64-bit

00:01:25

passed #68030
Linux
clang-c++11

00:01:50

passed #68032
Linux
cppcheck

00:00:38

passed #68037
Linux
doc

00:00:21

passed #68029
Linux
gcc-c++11

00:04:06

passed #68031
Apple
macos-c++11

00:01:35