scanFiles no longer throws an exception if the directory doesn't exist (PLAT-567)

Since the common use-case is that we want to check if there are any files
under a path, not check that the path exists, we make the default to not
throw.
Merge pull request #6 from datacratic/PLAT-567-scanFiles-no-exception-on-missing-directory

scanFiles no longer throws an exception if the directory doesn't exist (PLAT-567)
Merge branch 'master' of https://github.com/datacratic/jml into datacratic-internal-branch-4
Allow turning off boost erf (which crashes valgrind) (PLAT-568)

This allows you to compile with UNDER_VALGRIND=1 defined, which will avoid
the problematic code (note that it also stops IRLS from working, so it's
only a small workaround).

Has no impact unless enabled.
Merge pull request #7 from datacratic/PLAT-568-valgrind-crashing-boost-erf

Allow turning off boost erf (which crashes valgrind) (PLAT-568)
Merge branch 'master' of https://github.com/datacratic/jml into datacratic-internal-branch-4
Added missing header to wakeup_fd (TRIVIAL)

Needed for gcc 4.7 compilation, where the standard library brings less headers
in.
Merge pull request #8 from datacratic/TRIVIAL-wakeup_fd_missing_header

Added missing header to wakeup_fd (TRIVIAL)
Merge branch 'master' of https://github.com/datacratic/jml into datacratic-internal-branch-4