Add custom template for HexFiend

This allows to browse change index files

scripts/HexFiend/ChangeIndex.tcl

@@ -0,0 +1,67 @@
+proc varint {name {delta 0}} {
+    # loop through bytes reading protobuf varint
+    set value 0
+    set shift 0
+    set start_offset [pos]
+    while {1} {
+        set byte [uint8]
+        set value [expr {$value | (($byte & 0x7f) << $shift)}]
+        set shift [expr {$shift + 7}]
+        if {($byte & 0x80) == 0} {
+            set value [expr {$value + $delta}]
+            if {$name ne ""} {
+                entry $name $value [expr {[pos] - $start_offset}] $start_offset
+            }
+
+            return $value
+        }
+    }
+}
+
+proc account_id {name} {
+    set length [varint ""]
+    if {$length == 0} {
+        return ""
+    }
+    set value [str $length "utf8" $name]
+    return $value
+}
+
+proc buffer {name} {
+    set length [varint ""]
+    if {$length == 0} {
+        return ""
+    }
+    set value [hex $length $name]
+    return $value
+}
+
+while {![end]} {
+    section -collapsed "Account" {
+        set account [account_id "account"]
+        if {$account eq ""} {
+            endsection
+            break
+        }
+        sectionvalue $account
+
+        while {1} {
+            section "Key" {
+                set key [buffer "key"]
+                if {[string length $key] == 0} {
+                    endsection
+                    break
+                }
+                sectionvalue $key
+                section "Changes" {
+                    set changes_count [varint "count"]
+                    sectionvalue $changes_count
+                    set prev_change [varint "0"]
+                    for {set i 1} {$i < $changes_count} {incr i} {
+                        varint "$i" $prev_change
+                    }
+                }
+            }
+        }
+    }
+}