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

modules/beast_sqdb/source/statement.cpp

@@ -57,8 +57,8 @@
 */
 //==============================================================================
 
-namespace sqdb
-{
+namespace beast {
+namespace sqdb {
 
 statement::statement(session& s)
     : m_imp(new detail::statement_imp(s))
@@ -136,4 +136,5 @@ void statement::clean_up()
     m_imp->clean_up();
 }
 
-}
+} // sqdb
+} // beast