gnucash unstable: Test more thoroughly gnc-timezone's parsing of the zoneinfo database.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/ec9f60d3 (commit)
	from  https://github.com/Gnucash/gnucash/commit/98d41bc3 (commit)



commit ec9f60d3fd1dd2dbcecba8017225f40763f3f862
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat Dec 9 15:36:43 2017 -0800

    Test more thoroughly gnc-timezone's parsing of the zoneinfo database.
    
    Then fix the resulting problems.



Summary of changes:
 libgnucash/engine/gnc-timezone.cpp            |  58 ++++---
 libgnucash/engine/test/gtest-gnc-timezone.cpp | 211 +++++++++++++++++++++++++-
 2 files changed, 243 insertions(+), 26 deletions(-)