Issue #25027: Reverts partial-static build options and adds vcruntime140.dll to Windows installation.

Issue #22919: Windows build updated to support VC 14.0 (Visual Studio 2015), which will be used for the official 3.5 release.

solution.

Currently, Tix is not built in Debug configuration.

This change also:
- simplifies some Tcl/Tk-related msbuild properties for _tkinter
- copies the Tcl and Tk DLLs into the build output directory, meaning
  they will always be available after a build without having to copy
  them manually or change PATH
- removes PCbuild/build_tkinter.py: the solution does the build without
  needing to invoke Python (so Tcl/Tk/Tix can be built in parallel with
  the rest of the build using the `/m` msbuild command line switch)
- removes an outdated README concerning building Tcl/Tk on AMD64

use "references" to link to dependent projects.
Update readme and batch files.