Default config: Use strings for tag names

Tag names really are strings. Numbers just work accidentally since the C code
uses luaL_checklstring() to access the tag name and this function silently
converts numbers to strings.

This also has a nice documentation effect, making it easier for people to figure
out that they can change the name of a tag. Plus, with this the changes done by
previous commits make more sense (specifying an awful.rules-rule that identifies
a tag by name).

Signed-off-by: Uli Schlachter <psychon@znc.in>

awesomerc.lua

@@ -102,7 +102,7 @@ end
 tags = {}
 awful.screen.connect_for_each_screen(function(s)
     -- Each screen has its own tag table.
-    tags[s] = awful.tag({ 1, 2, 3, 4, 5, 6, 7, 8, 9 }, s, awful.layout.layouts[1])
+    tags[s] = awful.tag({ "1", "2", "3", "4", "5", "6", "7", "8", "9" }, s, awful.layout.layouts[1])
 end)
 -- }}}