Update and fix Windows CI builds

- boost-spirit dependency needed to be installed
- Visual Studio wanted boost/filesystem.hpp included in more places
- a deprecated enum was removed from new versions of boost, so we use
  its replacement enum now
- vcpkg repository is now pinned to a commit where boost 1.84 libraries
  work smoothly, there should be no more surprises
- vcpkg dependencies now cache, so successive CI runs are dramatically
  faster
- for win-scons, we need to use 'call' in our batch script to source
  vcvarsall.bat
- I updated the includepath and libpath we pass to win-scons to match
  reality, but it still can't find any vcpkg libraries. This will need
  further sleuthing

proj/vs2013/vcpkg.json

@@ -0,0 +1,18 @@
+{
+    "builtin-baseline": "bcf3d00d2116056fda0ce47615f6074ffecb7524",
+    "dependencies": [
+        "zlib",
+        "sfml",
+        "opengl",
+        "boost-any",
+        "boost-dynamic-bitset",
+        "boost-ptr-container",
+        "boost-core",
+        "boost-filesystem",
+        "boost-system",
+        "boost-date-time",
+        "boost-chrono",
+        "boost-math",
+        "boost-spirit"
+    ]
+}