Add a basic description of QPDF in README.md (fixes #552)

Also switch URLs for the qpdf and qtest websites to sourceforge.io
(https) instead of sourceforge.net (http).

NOTICE.md

@@ -8,7 +8,7 @@ Unless required by applicable law or agreed to in writing, software distributed
 
 Versions of qpdf prior to version 7 were released under the terms of version 2.0 of the Artistic License. At your option, you may continue to consider qpdf to be licensed under those terms. Please see the manual for additional information.
 
-The qpdf distribution includes a copy of [qtest](http://qtest.qbilt.org), which is released under the terms of the [version 2.0 of the Artistic license](https://opensource.org/licenses/Artistic-2.0), which can be found at https://opensource.org/licenses/Artistic-2.0.
+The qpdf distribution includes a copy of [qtest](https://qtest.sourceforge.io), which is released under the terms of the [version 2.0 of the Artistic license](https://opensource.org/licenses/Artistic-2.0), which can be found at https://opensource.org/licenses/Artistic-2.0.
 
 The Rijndael encryption implementation used as the basis for AES encryption and decryption support comes from Philip J. Erdelsky's public domain implementation.  The files `libqpdf/rijndael.cc` and `libqpdf/qpdf/rijndael.h` remain in the public domain.  They were obtained from
 * http://www.efgh.com/software/rijndael.htm

README-maintainer

@@ -142,7 +142,7 @@ RELEASE PREPARATION
 * Run a spelling checker over the source code to catch errors in
   variable names, strings, and comments.
 
-  make spell
+  make spell CLEAN=1
 
   This uses cspell. Install with `npm install -g cspell`. The output
   of cspell is suitable for use with `M-x grep` in emacs. Add

README.md

@@ -1,12 +1,14 @@
 # QPDF
 
-[![QPDF](logo/qpdf.svg)](http://qpdf.sourceforge.net)
+[![QPDF](logo/qpdf.svg)](https://qpdf.sourceforge.io)
 
 [![QPDF Build](https://github.com/qpdf/qpdf/workflows/QPDF%20Build/badge.svg)](https://github.com/qpdf/qpdf/actions)
 [![Total lgtm alerts](https://img.shields.io/lgtm/alerts/g/qpdf/qpdf.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/qpdf/qpdf/alerts/)
 [![Language grade on lgtm: C/C++](https://img.shields.io/lgtm/grade/cpp/g/qpdf/qpdf.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/qpdf/qpdf/context:cpp)
 
-This is the QPDF package.  Information about it can be found at http://qpdf.sourceforge.net.  The source code repository is hosted at GitHub: https://github.com/qpdf/qpdf.
+This is the QPDF package. QPDF is a command-line tool and C++ library that performs content-preserving transformations on PDF files. It supports linearization, encryption, and numerous other features. It can also be used for splitting and merging files, creating PDF files (but you have to supply all the content yourself), and inspecting files for study or analysis. QPDF does not render PDFs or perform text extraction, and it does not contain higher-level interfaces for working with page contents. It is a low-level tool for working with the structure of PDF files and can be a valuable tool for anyone who wants to do programmatic or command-line-based manipulation of PDF files.
+
+Additional information about it can be found at https://qpdf.sourceforge.io.  The source code repository is hosted at GitHub: https://github.com/qpdf/qpdf.
 
 # Verifying Distributions
 

appimage/qpdf.appdata.xml

@@ -31,7 +31,7 @@
 			can't password-protect them, web-optimize them, or perform other transformations of that type.</p>
 	</description>
 	<x-launchable type="desktop-id">qpdf.desktop</x-launchable>
-	<url type="homepage">http://qpdf.sourceforge.net/</url>
+	<url type="homepage">https://qpdf.sourceforge.io/</url>
 	<url type="bugtracker">https://github.com/qpdf/qpdf/issues</url>
 	<screenshots>
 		<screenshot type="default">

manual/qpdf-manual.xml

@@ -25,7 +25,7 @@
   <para>
    QPDF is a program that does structural, content-preserving
    transformations on PDF files.  QPDF's website is located at <ulink
-   url="http://qpdf.sourceforge.net/">http://qpdf.sourceforge.net/</ulink>.
+   url="https://qpdf.sourceforge.io/">https://qpdf.sourceforge.io/</ulink>.
    QPDF's source code is hosted on github at <ulink
    url="https://github.com/qpdf/qpdf">https://github.com/qpdf/qpdf</ulink>.
   </para>

qtest/README.txt

@@ -1,3 +1,3 @@
-This is a copy of qtest (http://qtest.qbilt.org) which is distributed
+This is a copy of qtest (https://qtest.sourceforge.io) which is distributed
 under the terms of the Artistic license and has the same author as
 qpdf.