Add examples/. Install to system on `make install`

Installs examples/* to /usr/share/pebblisp
A basic REPL is one of these examples, replacing the built-in C version
with one actually written in PebbLisp. It can be invoked the same way:
running `pl` without any arguments.

src/Makefile

@@ -18,3 +18,6 @@ run:
 
 install:
 	cp ./$(exe) /usr/bin/pl
+	mkdir -p /usr/share/pebblisp/
+	rm /usr/share/pebblisp/*
+	cp ./examples/* /usr/share/pebblisp/

src/examples/repl.pbl

@@ -0,0 +1,12 @@
+#!/usr/bin/pl
+(def repl (fn (_) (
+  (prn "pebblisp::> ")
+  (def input (inp 0))
+  (if (= input "q") () (
+    (prn (eval input))
+    (pch 10)
+    (repl 0)
+  ))
+)))
+
+(repl 0)

src/pebblisp.c

@@ -774,13 +774,7 @@ int readFile(const char *filename, struct Environment *env) {
 
 void repl(struct Environment *env)
 {
-    char input[200] = "";
-    while(input[0] != 'q') {
-        printf("pebblisp>> ");
-        fgets(input, 100, stdin);
-        Object obj = parseEval(input, env);
-        printAndClean(&obj);
-    }
+    readFile("/usr/share/pebblisp/repl.pbl", env);
 }
 
 int main(int argc, const char* argv[])