Optimize SQL query composition
Convert a unit test to manual
base_uint cleanups:
* Remove unused and broken reverse iterators
* Use charUnHex to reduce code duplication
Tidy up some source filenames:
* Add .unity suffix to mark unity sources
* Fix some relative include paths
Beast SCons tools:
* Add VSProject SCons Builder
* Add Protoc SCons Builder
* Add Beast build utilities python module
Improved SConstruct:
* Automatic source list built via directory iteration
* Build multiple toolchains and flavors simulaneously:
    - Toolchains: gcc, clang, msvc
    - Flavors: debug, release
* Documentation on aliases (top of the SConstruct file)
Fix rocksdb relative include
Tidy up includes
Add ci_char_traits
New http::client_session for making requests:
- Add 10,000 popular URL data set for unit tests
Fix clang/travis, prefer static libs when BOOST_ROOT is set.
Report whether a ledger is validated:
This addresses https://ripplelabs.atlassian.net/browse/RIPD-275
Use Json::StaticString to improve performance.
Use inject_error instead of manually adding errors.
Fix a few warnings
Fix VSProject generator item sort
Autobridging:
Complete implementation of bridged offers crossings. While processing an offer
A:B we consider both the A:B order book and the combined A:XRP and XRP:B books
and pick the better offers. The net result is better liquidity and potentially
better rates.

* Rearchitect core::Taker to perform direct and bridged crossings.
* Compute bridged qualities.
* Implement a new Bridged OfferCreate transactor.
* Factor out common code from the Bridged and Direct OfferCreate transactors.
* Perform flow calculations without losing accuracy.
* Rename all transactors.
* Cleanups.
Improve checking of library versions.

* Correctly handle openSSL version checking on Ubuntu, Debian, OS/X.
* Also check versions of openSSL, Boost, GCC and MSVC at C++ compile time.
* Get rid of over-engineered runtime CheckLibraryVersions.
Revert "Improve checking of library versions."

This reverts commit 69fccdf5c633cf217caeb45e0a8398485d38e194.
Detect paths with illegal bridging offers
Ste version to 0.25.2-rc1
Detect paths with illegal bridging offers