Add bootstrap note to INSTALL

INSTALL

@@ -17,6 +17,8 @@ main directory and do the following:
 
         $ ./configure
 
+     If configure does not exist you can create it with ./bootstrap
+
      If you are planning to install the package into your home directory
      or to a location other than `/usr/local' then add the flag
      `--prefix=PATH' to `configure'. For example, if your home directory