beast cleanup and tidying:

* Replace custom types with C++11 <cstdint> types
* Fix sqlite integer intos and uses
* Fix String implicit integer constructors
* Escape the enclosing namespace in sqdb
* Replace contract checks with assert
* Make many header files compile independently
* Remove the dependence on beast_core.h in many places
* Remove unused or obsolete classes and functions
* Remove unused or obsolete macros
* Remove unused network functions and files
* Remove unused or obsolete classes:
  - ChildProcess
  - HighResolutionTimer
  - InterProcessLock
  - Throw
  - TrackedMutex
  - UntrackedMutex
  - XmlDocument
  - XmlElement

src/ripple/json/impl/json_value.cpp

@@ -17,8 +17,9 @@
 */
 //==============================================================================
 
-namespace Json
-{
+#include "../../beast/modules/beast_core/text/LexicalCast.h"
+
+namespace Json {
 
 const Value Value::null;
 const Int Value::minInt = Int ( ~ (UInt (-1) / 2) );