Update README.md

http://cartodb.com/map 404 error.
Update README.md
Update README.md
Update README.md

changed POSTGIS_SQL_PATH='pg_config --sharedir'/contrib/postgis-2.0 to POSTGIS_SQL_PATH=`pg_config --sharedir`/contrib/postgis-2.0
Readme didn't say to connect to cartodb/base ppa
CDB-2757 Implemented sync now functionality along the way (@see ticket CDB-1100)
CDB-2757 Added superadmin endpoint for listing all users synchronizations
CDB-2757 Sync filter
Merge branch 'master' into CDB-2757
using https urls for cartodb basemaps CDB-2711
Merge pull request #353 from varunbhuvanendran/master

edit some links
Merge pull request #367 from varunbhuvanendran/patch-1

Update README.md
Merge remote-tracking branch 'origin/master' into CDB-2711
Merge pull request #394 from CartoDB/CDB-2711

using https urls for cartodb basemaps CDB-2711
CDB-2757 Finally found the issue with sync tables (error while moving from cdb_importer to public schemas caused data to not get updated), plus written a rake task to not need to rely on a daemon running ruby code (will use cron instead)
CDB-2757 Added rake option to trigger all syncs no matter if they should run or not
CDB-2789 #fixes Fixes marker-fill bug
Fixes spec
Merge pull request #395 from CartoDB/CDB-2789

CDB-2789 #fixes Fixes marker-fill bug
Fix wms spec