Add proposal 159 to index.

svn:r19114

doc/spec/proposals/000-index.txt

@@ -81,6 +81,7 @@ Proposals by number:
 156  Tracking blocked ports on the client side [OPEN]
 157  Make certificate downloads specific [ACCEPTED]
 158  Clients download consensus + microdescriptors [OPEN]
+159  Exit Scanning [OPEN]
 
 
 Proposals by status:
@@ -101,6 +102,7 @@ Proposals by status:
    149  Using data from NETINFO cells [for 0.2.1.x]
    156  Tracking blocked ports on the client side [for 0.2.?]
    158  Clients download consensus + microdescriptors
+   159  Exit Scanning
  ACCEPTED:
    110  Avoiding infinite length circuits [for 0.2.1.x] [in 0.2.1.3-alpha]
    117  IPv6 exits [for 0.2.1.x]