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

CodingStyle.md

@@ -120,7 +120,7 @@ overlooked. Blank lines are used to separate code into "paragraphs."
   `static_cast`. And when you're reinterpreting data, always use
   `reinterpret_cast`.
 * Until C++ gets a universal 64-bit primitive type (part of the C++11
-  standard), it's best to stick to the `int64` and `uint64` typedefs.
+  standard), it's best to stick to the `std::int64_t` and `std::uint64_t` typedefs.
 
 ## Object lifetime and ownership