Replace the PassThru driver with WinDivert package.
- Rename "divert.h" -> "tcpcrypt_divert.h" to avoid conflict.
- Correctly set DF_IN flag.
- divert.h now relies on -I flag
Update the win launcher and installer:
- Remove PassThru related cruft
- Install Divert related files
- Open two handles to divert to workaround the (currently) single-threaded
  divert driver.
- tcpcrypt.wxs tweaks.
Fix typo.
- WinDivert multithreading now works, so remove two-handle work-around.
- Update tcpcrypt.wxs to use divert binary release files.
Merge branch 'master' of https://github.com/basil00/tcpcrypt into win
autoconf
some minimal info on windivert
new installer