Update INSTALL.rst and CHANGELOG.rst for the sqlite dependency

CHANGELOG.rst

+Version 6.0
+===========
+
+ - The LiteSQL dependency was removed. Only libsqlite3 is now necessary
+   to work with the database.
+
 Version 5.0 - 2017-05-24
 ========================
 

CONTRIBUTING.rst

@@ -52,8 +52,8 @@ There are two test suites for biboumi:
   uses a specific IRC server (`charybdis`_), and only tests the most complete
   biboumi configuration (when all dependencies are used). To run it, you need
   to install various dependencies: refer to fedora’s `Dockerfile.base`_ and
-  `Dockerfile`_ to see how to install charybdis, slixmpp, botan, litesql, an
-  ssl certificate, etc.
+  `Dockerfile`_ to see how to install charybdis, slixmpp, botan, a ssl
+  certificate, etc.
 
   Once all the dependencies are correctly installed, the tests are run with
 
@@ -94,4 +94,4 @@ Please try to follow the existing style:
 .. _Dockerfile.base: docker/biboumi-test/fedora/Dockerfile.base
 .. _Dockerfile: docker/biboumi-test/fedora/Dockerfile
 .. _charybdis: https://github.com/charybdis-ircd/charybdis
-.. _the __main__.py file: tests/end_to_end/__main__.py
+.. _the __main__.py file: tests/end_to_end/__main__.py
\ No newline at end of file

INSTALL.rst

@@ -32,6 +32,12 @@ libiconv_
 libuuid_
  Generate unique IDs
 
+sqlite3_ (option, but highly recommended)
+ Provides a way to store various options in a (sqlite3) database. Each user
+ of the gateway can store their own values (for example their prefered port,
+ or their IRC password). Without this dependency, many interesting features
+ are missing.
+
 libidn_ (optional, but recommended)
  Provides the stringprep functionality. Without it, JIDs for IRC users are
  not provided.
@@ -48,11 +54,6 @@ libbotan_ 1.11 or 2.0 (optional)
 gcrypt_ (mandatory only if botan is absent)
  Provides the SHA-1 hash function, for the case where Botan is absent.
 
-litesql_ (optional)
- Provides a way to store various options in a (sqlite3) database. Each user
- of the gateway can store their own values (for example their prefered port,
- or their IRC password).
-
 systemd_ (optional)
  Provides the support for a systemd service of Type=notify. This is useful only
  if you are packaging biboumi in a distribution with Systemd.
@@ -160,7 +161,7 @@ to use biboumi.
 .. _libidn: http://www.gnu.org/software/libidn/
 .. _libbotan: http://botan.randombit.net/
 .. _udns: http://www.corpit.ru/mjt/udns.html
-.. _litesql: http://git.louiz.org/litesql
+.. _sqlite3: https://sqlite.org
 .. _systemd: https://www.freedesktop.org/wiki/Software/systemd/
 .. _biboumi.1.rst: doc/biboumi.1.rst
 .. _gcrypt: https://www.gnu.org/software/libgcrypt/