Fix set_group when no group is specified

Some pages that list contacts (e.g. when composing a message) issue a
set_group(0) on the addressbook object.

That means not restricting the search to a group at all, but the plugin
was trying to search for users belonging to a group with id = 0.
Merge pull request #16 from adobo/fix_listing

Fix set_group when no group is specified
check if debugging is enabled before calling the debug or debug_http functions
Merge pull request #17 from InuSasha/master

ignore the config.inc.php file
Provide an option to use only the local part of the email address

In case one uses the email address as username it is sometimes beneficial
to only use the local part of the email address as CardDAV username.
small change to documentation of %l
Fix group membership removal

Removing a contact from a single group caused it to be removed from every
group the contact was in, at least on the database. vCard were modified as
expected.

This commit adds an $other_conditions argument to the delete_dbrecord() method,
which is used by remove_from_group() to specify which group the contact has to
be removed from.
Merge pull request #19 from adobo/fix_group_membership

Fix group membership removal
Add "IF NOT EXISTS" to create table statements for Postgres
update INSTALL file with text provided by Juergen Edner
Merge branch 'jp-postgres-sql' of git://github.com/jplock/rcmcarddav into jplock-jp-postgres-sql
Fix use of insert_id function in RC 1.0-rc
Make the schema like the one in RoundCube 1.0-rc
Merge pull request #21 from kearva/master

Fix changes done in RoundCube 1.0-rc
Merge branch 'master' of github.com:blind-coder/rcmcarddav

Conflicts:
	dbinit/postgres.sql
fix conflicts
increase version number to 1.0.0