gnucash master: Convert boost::filesystem path strings to utf8.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/d6677ff3 (commit)
	from  https://github.com/Gnucash/gnucash/commit/75cc34a2 (commit)



commit d6677ff39f106a391c646142e991888b1ab8c4a6
Author: Geert Janssens <geert at kobaltwit.be>
Date:   Thu Aug 31 20:06:27 2017 +0200

    Convert boost::filesystem path strings to utf8.
    
    Fixes windows build.



Summary of changes:
 libgnucash/core-utils/CMakeLists.txt         |  7 ++++-
 libgnucash/core-utils/gnc-filepath-utils.cpp | 43 ++++++++++++++++++++++------
 2 files changed, 41 insertions(+), 9 deletions(-)