README: Move readme.pod from doc/pod to top-level directory

It will permit displaying the GitHub-traditional README file when
accessing the INN repository.
Do not duplicate our already existing readme.pod file for that (GitHub
handles fine POD files).

MANIFEST

@@ -326,7 +326,6 @@ doc/pod/qio.pod                       Master file for qio.3
 doc/pod/radius.pod                    Master file for radius.8
 doc/pod/rc.news.pod                   Master file for rc.news.8
 doc/pod/readers.conf.pod              Master file for readers.conf.5
-doc/pod/readme.pod                    Master file for README
 doc/pod/rnews.pod                     Master file for rnews.1
 doc/pod/scanlogs.pod                  Master file for scanlogs.8
 doc/pod/scanspool.pod                 Master file for scanspool.8
@@ -647,6 +646,7 @@ perl/INN/Config.pm.in                 INN::Config module
 perl/INN/Utils                        INN::Utils Perl modules (Directory)
 perl/INN/Utils/Shlock.pm.in           INN::Utils::Shlock module
 perl/Makefile                         Makefile for perl libraries
+readme.pod                            Master file for README
 samples                               Prototype INN config files (Directory)
 samples/INN.py                        Stub Python functions
 samples/Makefile                      Makefile for samples

doc/pod/Makefile

@@ -59,7 +59,7 @@ maintclean: distclean
 ../../HACKING:		hacking.pod		; $(POD2TEXT) $? > $@
 ../../INSTALL:		install.pod		; $(POD2TEXT) $? > $@
 ../../NEWS:		news.pod		; $(POD2TEXT) $? > $@
-../../README:		readme.pod		; $(POD2TEXT) $? > $@
+../../README:		../../readme.pod	; $(POD2TEXT) $? > $@
 ../checklist:		checklist.pod		; $(POD2TEXT) $? > $@
 ../external-auth:	external-auth.pod	; $(POD2TEXT) $? > $@
 ../hook-perl:		hook-perl.pod		; $(POD2TEXT) $? > $@

doc/pod/hacking.pod

@@ -774,7 +774,7 @@ release of that major release.
     git checkout -b Y.Y
 
 Then, in that newly created branch, remove the first paragraph in
-F<doc/pod/readme.pod> which deals with development versions.
+F<readme.pod> which deals with development versions.
 
 =item 8.
 
@@ -879,7 +879,7 @@ tag in Git:
 =item 16.
 
 Bump revision numbers to reflect the one of the following release,
-especially in F<doc/pod/install.pod> and F<doc/pod/readme.pod>
+especially in F<doc/pod/install.pod> and F<readme.pod>
 for major releases, F<configure.ac> and F<Makefile.global.in> for both
 minor and major releases.  The release versions in the GitHub bug tracker
 should also be updated.