Fix global substitution (#94)

Signed-off-by: David P. Chassin <dchassin@slac.stanford.edu>
Signed-off-by: David P. Chassin <david.chassin@me.com>

source/autotest/test_inline_global_replacement.glm

@@ -0,0 +1,4 @@
+// verify that issue #32 is fixed
+#if "${modelname/.csv/.json}" != "${modelname}"
+#error Global replacement failed
+#endif

source/globals.cpp

@@ -1263,11 +1263,11 @@ bool GldGlobals::parameter_expansion(char *buffer, size_t size, const char *spec
 		size_t start;
 		if ( global_getvar(name,temp,sizeof(temp)-1)==NULL )
 			return 0;
-		strcpy(buffer,"");
+		strcpy(buffer,temp);
 		while ( true )
 		{
 			ptr = strstr(temp,pattern);
-			if ( ptr==NULL )
+			if ( ptr == NULL )
 				break;
 			start = ptr - temp;
 			strncpy(buffer,temp,size);
@@ -1285,9 +1285,9 @@ bool GldGlobals::parameter_expansion(char *buffer, size_t size, const char *spec
 		size_t start;
 		if ( global_getvar(name,temp,sizeof(temp)-1)==NULL )
 			return 0;
-		strcpy(buffer,"");
+		strcpy(buffer,temp);
 		ptr = strstr(temp,pattern);
-		if ( ptr!=NULL )
+		if ( ptr != NULL )
 		{
 			start = ptr - temp;
 			strncpy(buffer,temp,size);