Added USERLIB with prepend and set.

Added a q shortcut to quote
get-doc and set-doc no longer conditionally evaluate args
Fixed bug in let, documented potential performance improvements
upped default history to 5k lines

src/stl/control.rs

@@ -205,8 +205,13 @@ pub fn let_callback(ast: &Seg, syms: &mut SymTable) -> Result<Ctr, String> {
 
     // we need to get any var declared from within the let eval forms
     // those need to exist in the outside context
+    // TODO: make this more optimal
+    //     How can we skip iterations?
+    //     implement a counter for number of calls to def
+    //     store it inside the SymTable and Symbol
+    //     only re-insert into global scope what is most recent
     for i in localsyms.iter() {
-        if !locals.contains(i.0) && !syms.contains_key(i.0) {
+        if !locals.contains(i.0) {
             syms.insert(
                 i.0.clone(),
                 i.1.clone(),