Build system improvements:

* Reduce console verbosity.
* Display configured build environment.
* Log build environment and commands in rippled-build.log.
* When compiling under Travis:
  - define TRAVIS_CI_BUILD for C and C++ code.
  - define RIPPLE_MASTER_BUILD for builds made against
    the official Ripple repository.
[FOLD] Fix typo
[FOLD/TX-REFAC] WalletAdd Transactor journal
[FOLD/TX-REFAC] TrustSet Transactor journal
[FOLD/TX-REFAC] RegularKeySet Transactor journal
[FOLD/TX-REFAC] Payment Transactor journal