Replace phpBB Group with phpBB Limited

EXTTOOLS-654

- "phpBB Group" replaced with "phpBB Limited"
Replace phpBB Group with phpBB Limited

EXTTOOLS-654

- Update: "style.css" header based on phpBB "stylesheet.css" header
"http://www.phpbb.com" replaced with "https://www.phpbb.com"

EXTTOOLS-654
Fix header indentation

EXTTOOLS-654
Merge pull request #34 from phpbb-fr-com/qi-exttools-654

Quickinstall: exttools 654
Added "purge_cache" to the ignore list.
Changed version to 1.2.0
Spelling errors.
Bug in the routine to purge the cache.
Ticket #EXTTOOLS-655 The redirect got two slashes in the URL when QI was installed in localhost root.
Bump the version number. 1.2.1-dev
Moved the "can take a while" warning box and the options/settings boxes.
Added better error reporting and handling to more places.
Don't show the select menu for alternative environments if the phpBB3_alt folder is empty.
Write correct phpBB version (3.1 or 3.0) in cofig.php.
Show board version in boards list.
Update CHANGELOG

correct a little spelling mistake
Merge pull request #35 from Un1matr1x/patch-1

Update CHANGELOG
Make sure cache_dir, boards_dir and boards_url ends with a slash.
Always seem to forget this file.