Bulk (mostly documentation) update

 - Remove PHP version from license notices
 - Bump year number in copyright notices
 - Recommend PHP 5.4 or newer to be used
 - Tell Travis-CI to test on PHP 5.3.0 instead of the latest 5.3 version

Related: #3450
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 05442d8..42ef52c 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -13,7 +13,7 @@
 
 -  General Changes
 
-   -  PHP 5.1.6 is no longer supported. CodeIgniter now requires PHP 5.2.4.
+   -  PHP 5.1.6 is no longer supported. CodeIgniter now requires PHP 5.2.4 and recommends PHP 5.4+ or newer to be used.
    -  Changed filenaming convention (class file names now must be Ucfirst and everything else in lowercase).
    -  Changed the default database driver to 'mysqli' (the old 'mysql' driver is DEPRECATED).
    -  ``$_SERVER['CI_ENV']`` can now be set to control the ``ENVIRONMENT`` constant.