VS: Adapt project parsers to support "ProjectGUID" without curly brackets

This is needed to correctly parse Windows Installer "wiproj" projects,
that by default contain "ProjectGUID" tags with GUID values without
surrounding curly brackets.  Otherwise CMake truncates the first & last
character from the GUID value for these projects.

Source/cmLocalVisualStudio10Generator.cxx

@@ -17,7 +17,12 @@ public:
   virtual void CharacterDataHandler(const char* data, int length)
   {
     if (this->DoGUID) {
-      this->GUID.assign(data + 1, length - 2);
+      if (data[0] == '{') {
+        // remove surrounding curly brackets
+        this->GUID.assign(data + 1, length - 2);
+      } else {
+        this->GUID.assign(data, length);
+      }
       this->DoGUID = false;
     }
   }

Source/cmLocalVisualStudio7Generator.cxx

@@ -2079,7 +2079,10 @@ public:
         if (strcmp(atts[i], "ProjectGUID") == 0) {
           if (atts[i + 1]) {
             this->GUID = atts[i + 1];
-            this->GUID = this->GUID.substr(1, this->GUID.size() - 2);
+            if (this->GUID[0] == '{') {
+              // remove surrounding curly brackets
+              this->GUID = this->GUID.substr(1, this->GUID.size() - 2);
+            }
           } else {
             this->GUID.clear();
           }