* `get_http_url()` renamed to `get_http_response()`.
* Use the same HTTP context to retrieve response headers and content.
* Follow HTTP 301 and 302 redirections to retrieve the title (default max 3 redirections).
* Add `LinkUtils` to extract titles and charset.
* Try to retrieve charset from HTTP headers first (new), then HTML content.
* Use mb_string to re-encode title if necessary.
Relates to #40
Relates to #372
Additions:
- FileUtils: IOException
- ApplicationUtils:
- check if Shaarli resources are accessible with sufficient permissions
- basic test coverage
- index.php:
- check access permissions and redirect to an error page if needed:
- before running the first installation
Modifications:
- LinkDB:
- factorize datastore write code
- check if the datastore
(exists AND is writeable) OR (doesn't exist AND its parent dir is writable)
- raise an IOException if needed
Signed-off-by: VirtualTam <virtualtam@flibidi.net>