Introduced (organizational) units

- New table "unit"
- Each "area" refers to one unit
- "invite_code"s are valid for one or many units
- New table "privilege" stores "voting_right" for units
- Delegation scope 'global' is replaced by delegation scope 'unit'
- View "global_delegation" is replaced by "unit_delegation"
- Removed helper view "active_delegation"
- Checking that members have "voting_right" in several views and functions
- New view "unit_member_count" to update "member_count" column of new unit table
- New argument list for function "delegation_chain"(...) containing "unit_id"
- Renamed column "member_active" to "member_valid" in "delegation_chain_row"
- Modified demo.sql and init.sql to support units

     1.1 --- a/init.sql	Mon Dec 06 23:50:32 2010 +0100
     1.2 +++ b/init.sql	Tue Dec 07 00:04:44 2010 +0100
     1.3 @@ -2,6 +2,17 @@
     1.4  
     1.5  BEGIN;
     1.6  
     1.7 +INSERT INTO "unit" (
     1.8 +        "active",
     1.9 +        "name",
    1.10 +        "description"
    1.11 +    ) VALUES (
    1.12 +        true,
    1.13 +        'Default unit',
    1.14 +        'Default unit created by init script.'
    1.15 +    );
    1.16 +        
    1.17 +
    1.18  INSERT INTO "member" (
    1.19          "login",
    1.20          "password",
    1.21 @@ -63,10 +74,12 @@
    1.22          1, 100 );
    1.23  
    1.24  INSERT INTO "area" (
    1.25 +        "unit_id",
    1.26          "active",
    1.27          "name",
    1.28          "description"
    1.29      ) VALUES (
    1.30 +        1,
    1.31          TRUE,
    1.32          'Generic area',
    1.33          DEFAULT );