cl-lexer: Move lexer into its own crate

cl-repl/examples/collect-identifiers.rs

@@ -1,9 +1,9 @@
 //! Collects identifiers into a list
 
+use cl_lexer::Lexer;
 use cl_parser::Parser;
 use cl_repl::repline::Repline;
 use cl_structures::span::Loc;
-use conlang::lexer::Lexer;
 use std::{
     collections::HashMap,
     error::Error,

cl-repl/examples/identify_tokens.rs

@@ -1,7 +1,7 @@
 //! This example grabs input from stdin, lexes it, and prints which lexer rules matched
 #![allow(unused_imports)]
+use cl_lexer::Lexer;
 use cl_token::Token;
-use conlang::lexer::Lexer;
 use std::{
     error::Error,
     io::{stdin, IsTerminal, Read},