added an alias cp for the fs.copy function

exec/shell.lua

@@ -7,6 +7,7 @@ function shenv.quit()
 end
 shenv.cd = os.chdir
 shenv.mkdir = fs.makeDirectory
+shenv.cp = fs.copy
 local function findPath(name)
  path = os.getenv("PATH") or "/boot/exec"
  for l in path:gmatch("[^\n]+") do