Phase 1 work to add PDO and move settings $config to the API.

This MR is the first step in addressing #149 to remove Adodb

• Adds PDO Extension to compose
• Adds PDO & PDO Mysql Extenstion test to installer.
• Setups PDO Connection in OpenRealty\API namespace
• Moves retrieval of $config to a new SettingsApi
• Updates Installer to write DB Settings to a ini file in the api folder.
• Update All API Commands to accept the PDO dbh as at construction.
• Update All API Commands to accept setings at construction.
• Update all Open-Realty Classes to accept Settings at construction.
• Remove all references to global $config.
• Update all OpenRealty Classes to accept PDO dbh at construction
• Update all API Calls to pass in PDO db and Settings.
• Update Hooks to get passed $dbh and $config (This is done, but not correctly needs rework before merging. Should pass by class construct instead of each function.)
• Update Addons to get passed $dbh and $config

Phase 2

• Replace all uses of adodb in API with PDO
  • LogApi
  • BlogAPi
  • ListingApi
  • FieldsApi
  • MediaApi
  • PageApi
  • PClassApi
  • SettingsApi
  • TwitterApi
  • UserApi

Phase 3

• Work to replace all non API calls to database with API calls.
• Remove Adodb

Extras (Test feasibility)

• Consolidate index.php, ajax.php, admin/index.php, admin/ajax.php, aand pingback.php into a single file..