Update Tcl/Tk to 8.6.3

- new file dialogs on Vista+
- tclWinTime.c was cleaned up a bit, and no
  longer uses 'timezone' (which is now _timezone
  in VS2015, so we get to avoid patching that
  file).
- rules.vc is patched in both Tcl and Tk sources
  to allow building with VS2015

PCbuild/get_externals.bat

@@ -55,8 +55,8 @@ for %%e in (
             bzip2-1.0.6
             nasm-2.11.06
             openssl-1.0.1j
-            tcl-8.6.1.0
-            tk-8.6.1.0
+            tcl-core-8.6.3.1
+            tk-8.6.3.1
             tix-8.4.3.4
             sqlite-3.8.3.1
             xz-5.0.5

PCbuild/tcltk.props

@@ -4,8 +4,8 @@
   <PropertyGroup>
     <TclMajorVersion>8</TclMajorVersion>
     <TclMinorVersion>6</TclMinorVersion>
-    <TclPatchLevel>1</TclPatchLevel>
-    <TclRevision>0</TclRevision>
+    <TclPatchLevel>3</TclPatchLevel>
+    <TclRevision>1</TclRevision>
     <TkMajorVersion>$(TclMajorVersion)</TkMajorVersion>
     <TkMinorVersion>$(TclMinorVersion)</TkMinorVersion>
     <TkPatchLevel>$(TclPatchLevel)</TkPatchLevel>
@@ -14,7 +14,7 @@
     <TixMinorVersion>4</TixMinorVersion>
     <TixPatchLevel>3</TixPatchLevel>
     <TixRevision>4</TixRevision>
-    <tclDir>$(ExternalsDir)tcl-$(TclMajorVersion).$(TclMinorVersion).$(TclPatchLevel).$(TclRevision)\</tclDir>
+    <tclDir>$(ExternalsDir)tcl-core-$(TclMajorVersion).$(TclMinorVersion).$(TclPatchLevel).$(TclRevision)\</tclDir>
     <tkDir>$(ExternalsDir)tk-$(TkMajorVersion).$(TkMinorVersion).$(TkPatchLevel).$(TkRevision)\</tkDir>
     <tixDir>$(ExternalsDir)tix-$(TixMajorVersion).$(TixMinorVersion).$(TixPatchLevel).$(TixRevision)\</tixDir>
     <tcltkDir>$(ExternalsDir)tcltk\</tcltkDir>