Add git-checkout-tag script.

For tag 'FOO-1.0':

$ git checkout-tag FOO-1.0
Switched to a new branch 'FOO-1.0-branch'

Just avoids confusing branch names.

bin/git-checkout-tag

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+
+# checkout a tag "FOO-1-0" into a branch called "FOO-1-0-branch"
+
+checkout-tag() 
+{
+    tagname="${1:-}"
+    if [[ "${tagname}" ]] ; then
+        branchname="${tagname}"-branch
+        git checkout -b "${branchname}" "${tagname}"
+    fi
+}
+
+checkout-tag "$@"

gitconfig

@@ -52,8 +52,8 @@
     command = true
 
 
-[diff "podiff"]
-    #textconv = /usr/bin/podiff -t
+#[diff "podiff"]
+#    textconv = /usr/bin/podiff -t
     #command = /usr/bin/podiff -D-u -L
 
 #
@@ -346,6 +346,9 @@
     # usage: `git whatadded --foo.c`
     whatadded = log --follow --diff-filter=A --find-renames=40%
 
+    # checkout a tag into a branch
+    checkout-tag = "!f() { tagname=${1}; branchname='${tagname}-branch'; git checkout -b '${branchname}' '${tagname}'; } ; f"
+
 # show a specifc version of a file
 # git show rev:filename