* Use nullptr (C++11) instead of NULL.
* Put each file into its own namespace declaration.
* Remove "using namespace" directives and add scope qualifiers.
* Control when beast's implementation of std::equal (C++14) is used.
* Tidy up some const declarations.
Conflicts:
src/ripple_app/shamap/SHAMapSync.cpp
src/ripple_app/tx/TransactionEngine.cpp