Improve design of actualize notification

- Remove progress bar
- Show title of updated feed
Add possibility to keep logged in with form

Add an option to keep logged in.
Change lifetime of session cookie to 1 year.

See https://github.com/marienfressinaud/FreshRSS/issues/465
Forget to change the i18n string

See https://github.com/marienfressinaud/FreshRSS/issues/465
Update CHANGELOG

Add option to stay logged in
Change cookie lifetime to 1 month.

See https://github.com/marienfressinaud/FreshRSS/issues/465
Add 1 month indication for "keep me logged in"

.prompt .form is also now larger

See https://github.com/marienfressinaud/FreshRSS/issues/465
Set session.gc_maxlifetime

Take the maxvalue between 1440 (24m) and cookie lifetime when calling
Minz_Session::keepCookie()

See https://github.com/marienfressinaud/FreshRSS/issues/465
Revert "Set session.gc_maxlifetime"

This reverts commit df47217839ccddb8e03015959c61b61e748d9700.

See https://github.com/marienfressinaud/FreshRSS/issues/465
Improve system import/export

Miss checking presence of zip extension during import

See https://github.com/marienfressinaud/FreshRSS/issues/494
Improve import system

Catch errors of zip_open and log it. A notification is shown to indicate
something went wrong.

See https://github.com/marienfressinaud/FreshRSS/issues/494
gitignore /p/i/.htaccess

This can be the place of a user's .htaccess, for instance for HTTP
password control.
New wrappers Minz_Request::good() and bad()

1. Set a notification message in session variable
2. Redirect to a specific url

First use in importExportController.php

See https://github.com/marienfressinaud/FreshRSS/conversations/576
Use REQUEST_URI instead of SCRIPT_NAME for cookies

See https://github.com/marienfressinaud/FreshRSS/commit/eceb7756cfcf117c2a18984291181a84697ed3cd#commitcomment-7345438
Fix a Minz_Session TODO

Not use additional variable to manipulate session variables
Fix coding style
Fix coding style of Minz_Request
Fix missing REQUEST_METHOD

Useful when executing actualize_script.php
Move htmlspecialchars_utf8 from Request to Helper

And remove html_chars_utf8 to use htmlspecialchars_utf8 instead in
importExportController
Coding style in Minz_Helper
Merge branch 'dev' of github.com:marienfressinaud/FreshRSS into dev
Fix missing Minz_ prefix in Minz_Helper

Nice bug :) It means another hidden bug is now corrected!