Use soci in some places:

* Brings the soci subtree into rippled.
* Validator, peerfinder, and SHAMapStore use new soci backend.
* Optional postgresql backend for soci (if POSTGRESQL_ROOT env var is set).

src/ripple/core/ConfigSections.h

@@ -20,6 +20,8 @@
 #ifndef RIPPLE_CORE_CONFIGSECTIONS_H_INCLUDED
 #define RIPPLE_CORE_CONFIGSECTIONS_H_INCLUDED
 
+#include <string>
+
 namespace ripple {
 
 // VFALCO DEPRECATED in favor of the BasicConfig interface

src/ripple/core/tests/Config.test.cpp

@@ -20,6 +20,7 @@
 #include <BeastConfig.h>
 #include <ripple/core/impl/LoadFeeTrackImp.h>
 #include <ripple/core/Config.h>
+#include <ripple/core/ConfigSections.h>
 #include <ripple/basics/TestSuite.h>
 #include <boost/filesystem.hpp>
 #include <boost/format.hpp>