gnucash unstable: Multiple changes pushed

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/ebbcd30f (commit)
	 via  https://github.com/Gnucash/gnucash/commit/fcf88262 (commit)
	from  https://github.com/Gnucash/gnucash/commit/e798df07 (commit)



commit ebbcd30f398e589abbaf1efbeb99d74cb04ba951
Author: John Ralls <jralls at ceridwen.us>
Date:   Tue Jan 9 14:58:43 2018 -0800

    Save Changes Bug 792106 - Wrong dates displayed
    
    The first attempt to fix this, a17bc85a, doesn't work because the
    boost::date_time constructor gets enough information in most cases to
    generate a date, just not the one we expect. This change looks for '-' in
    the fourth position and if it's there assumes iso-extended format, otherwise
    it assumes delimiter-less ISO without the 'T', i.e. %Y%m%d%H%M%S.

commit fcf88262ca036439c711d91d2a8e7bf892f49b21
Author: John Ralls <jralls at ceridwen.us>
Date:   Tue Jan 9 13:58:25 2018 -0800

    Extract function tz_from_string.
    
    Also changes from calculating the Bug 767824 offset to using
    boost::date_time::local_time_in() and provides unit tests.



Summary of changes:
 libgnucash/engine/gnc-datetime.cpp            | 78 +++++++++++----------------
 libgnucash/engine/test/gtest-gnc-datetime.cpp | 45 +++++++++++++---
 2 files changed, 71 insertions(+), 52 deletions(-)