Rename --null to --read0 and undocument the option

`--null` is ambiguous. For completeness' sake, we need both `--read0`
and `--print0`.

`--read0` only makes sense when the input contains multiline entries.
However, fzf currently cannot correctly display multiline entries,
I'm going to make `--read0` an undocumented feature.

fzf

@@ -206,10 +206,10 @@ class FZF
         @expect = true
       when /^--expect=(.*)$/
         @expect = true
-      when '--toggle-sort', '--tiebreak', '--color', '--bind', '--history', '--history-max'
+      when '--toggle-sort', '--tiebreak', '--color', '--bind', '--history', '--history-size'
         argv.shift
       when '--tac', '--no-tac', '--sync', '--no-sync', '--hscroll', '--no-hscroll',
-           '--inline-info', '--no-inline-info', '--null', /^--bind=(.*)$/,
+           '--inline-info', '--no-inline-info', '--read0', '--cycle', /^--bind=(.*)$/,
            /^--color=(.*)$/, /^--toggle-sort=(.*)$/, /^--tiebreak=(.*)$/, /^--history(-max)?=(.*)$/
         # XXX
       else

src/options.go

@@ -50,7 +50,6 @@ const usage = `usage: fzf [options]
     -1, --select-1        Automatically select the only match
     -0, --exit-0          Exit immediately when there's no match
     -f, --filter=STR      Filter mode. Do not start interactive finder.
-        --null            Read null-byte separated strings from input
         --print-query     Print query as the first line
         --expect=KEYS     Comma-separated list of keys to complete fzf
         --sync            Synchronous search for multi-staged filtering
@@ -679,8 +678,10 @@ func parseOptions(opts *Options, allArgs []string) {
 			opts.Exit0 = true
 		case "+0", "--no-exit-0":
 			opts.Exit0 = false
-		case "--null":
+		case "--read0":
 			opts.ReadZero = true
+		case "--no-read0":
+			opts.ReadZero = false
 		case "--print-query":
 			opts.PrintQuery = true
 		case "--no-print-query":

test/test_go.rb

@@ -518,10 +518,10 @@ class TestGoFZF < TestBase
     assert_equal data, `cat #{tempname} | #{FZF} -f .`.chomp
   end
 
-  def test_null
+  def test_read0
     lines = `find .`.split($/)
     assert_equal lines.last, `find . | #{FZF} -e -f "^#{lines.last}$"`.chomp
-    assert_equal lines.last, `find . -print0 | #{FZF} --null -e -f "^#{lines.last}$"`.chomp
+    assert_equal lines.last, `find . -print0 | #{FZF} --read0 -e -f "^#{lines.last}$"`.chomp
   end
 
   def test_select_all_deselect_all_toggle_all