Merge branch 'mr/sort-refs-by-type'

* mr/sort-refs-by-type:
  gitk: separate upstream refs when using the sort-by-type option
  gitk: make 'sort-refs-by-type' optional and persistent
  gitk: sort by ref type on the 'tags and heads' view

diff --cc gitk
index fa0d9a94e5fddf7dbdd7733d9d6a0a4d63c4cf47,38c2c81a79eb31dddd23f2f7507a0638c71992a8..153ca3e64037f94c8cfde24cfdc46e0ca45c6162
--- 1/gitk
--- 2/gitk
+++ b/gitk
@@@ -1979,9 -1976,8 +1979,9 @@@ proc readrefs {} 
      global selecthead selectheadid
      global hideremotes
      global tclencoding
 +    global hashlength
  
-     foreach v {tagids idtags headids idheads otherrefids idotherrefs} {
+     foreach v {tagids idtags headids idheads otherrefids idotherrefs upstreamofref} {
          unset -nocomplain $v
      }
      set refd [safe_open_command [list git show-ref -d]]