Added cosmoV_pushFString(), and cosmoO_pushVFString().

cosmoV_error now pushes the error string onto the stack, as well as uses cosmoO_VFString to format strings.
cosmoV_concat is now entirely self contained, and is now stack based. Push the CValues you want to concat into strings onto the stack and call cosmoV_concat with the # of values you pushed.

src/main.c

@@ -52,6 +52,7 @@ static void repl() {
     cosmoB_loadLibrary(state);
     cosmoB_loadDebug(state);
 
+    // add our custom REPL functions
     cosmoV_pushString(state, "quit");
     cosmoV_pushCFunction(state, cosmoB_quitRepl);
 
@@ -111,6 +112,12 @@ static void runFile(const char* fileName) {
     CState *state = cosmoV_newState();
     cosmoB_loadLibrary(state);
 
+    // add our input() function to the global table
+    cosmoV_pushString(state, "input");
+    cosmoV_pushCFunction(state, cosmoB_input);
+
+    cosmoV_register(state, 1);
+
     interpret(state, script, fileName);
 
     cosmoV_freeState(state);