Parsing version info fails with newer vcpkg versions.

[henrik-jensen]

vcpkg has changed the output of command vcpkg version so that the parsing of the output string is broken.
Output of newer versions that fails:

C:\src\vcpkg>vcpkg version
Vcpkg package management program version 2018.10.20-nohash

See LICENSE.txt for license information.

and result in a runtime exception:

System.ArgumentOutOfRangeException
  HResult=0x80131502
  Message=Længden må ikke være mindre end nul. [1]

[1] In english "Length can't be less than zero"*

in UserInterface\MainWindow.xaml.cs line 65.

"C:\Users\henrik\Source\Repos\vcpkg-gui\UserInterface\MainWindow.xaml.cs"
65:            BuildDate = vstr.Substring(splitHead + 1, splitEnd - splitHead - 1);

For comparison output from an older version that works with vcpkg-gui:

C:\src\vcpkg_old>vcpkg version
Vcpkg package management program version 0.0.104-2018-02-07-d503a55412b3fa1b2b96ae0719286ee593f3d732

See LICENSE.txt for license information.