Make `list` search terms match anywhere on the line

Making list more flexible enables searching for hostnames as well as
partial ip addresses.

Readme.md

@@ -7,7 +7,7 @@ A command line program with shortcuts for managing hosts file entries.
     Usage:
       hosts add <ip> <hostname>
       hosts remove <hostname>
-      hosts list [127.]
+      hosts list [<search string>]
       hosts edit
       hosts file
 

hosts

@@ -702,7 +702,7 @@ Description:
 EOM
 list() {
   if [[ -n "$1" ]]; then
-    grep "^$1" /etc/hosts
+    grep "^[^#]*$1" /etc/hosts
   else
     # NOTE: use separate expressions since using a | for the or results in
     # inconsistent behavior.