undocumented dependency on xdebug.extended_info configuration

[colinlieberman]

If this is documented elsewhere, my apologies for missing it.

If you turn the xdebug.extended_info config off, the step debugger won't stop at breakpoints.

Here's a diff for noting that in the readme:

diff --git a/README.md b/README.md
index 1ca6359..404cecd 100644
--- a/README.md
+++ b/README.md
@@ -34,6 +34,7 @@ xdebug.remote_port=9000
 xdebug.remote_handler=dbgp
 xdebug.remote_mode=req
 xdebug.remote_autostart=true
+xdebug.extended_info=1 # This is on by default; php-debug won't work if it's disabled
 ```
 
 With these settings, PHP will connect to your editor for every script it executes.