Restore correct public interface of getUserData() for authldap
plugin

The outer/public getUserData() implemented as a wrapper for the
previous fn which is now protected.
Allow user info to be retrieved without groups

Some parts of dokuwiki (e.g. recent changes, old revisions) can
requests lots of user info (to provide editor names) without
requiring any group information.

This change also implements caching of user info by authmysql &
authpgsql plugins to avoid repeated querying of the DB to retrieve
the same user information.
code styling - add missing braces
fix comment errors, sp. & grammar
use $requireGroups constants in auth classes; comments; code improvements
KISS - remove class constants for REQUIRE_GROUPS & IGNORE_GROUPS and replace with boolean values
adding X-Forwarded-Proto support in is_ssl()

This commit adds support for X-Forwarded-Proto in case dokuwiki runs
behind a reverse (SSL) proxy, but the connection between the proxy and
the web server running dokuwki is plain HTTP. If an authenticated
user is accidentaly dropped to HTTP from HTTPS the securecookie setting
should be honored and the redirection when saving or canceling a page
edit should point to the correct protocol. This happens every time a
user hits cancel after editing a page, and likely even after saving. If
the webserver doesn't enforce HTTPS the coockie might be sent in clear.
Adding unit test for is_ssl()

this should test the correctness of the return value of is_ssl()
function based on various combinations of PHP environment variables
translation update
improve qsearch suggestions

* support namespaces with more then one level e.g. @your:namespace
* support ns:<ns> as well
Added @ALL handeling in auth_isMember
Merge pull request #822 from jurrehart/Issue#637

Added @ALL handeling in auth_isMember
Merge remote-tracking branch 'origin/pr/814'

* origin/pr/814:
  translation update

Conflicts:
	inc/lang/ta/lang.php
Merge pull request #799 from enricotagliavini/master

Adding X-Forwarded-Proto support
Merge pull request #821 from splitbrain/searchns

improve qsearch suggestions
Merge remote-tracking branch 'origin/auth_getUserData_improvements'

* origin/auth_getUserData_improvements:
  KISS - remove class constants for REQUIRE_GROUPS & IGNORE_GROUPS and replace with boolean values
  use $requireGroups constants in auth classes; comments; code improvements
  fix comment errors, sp. & grammar
  code styling - add missing braces
  Allow user info to be retrieved without groups
  Restore correct public interface of getUserData() for authldap plugin

Conflicts:
	inc/common.php