gnucash maint: Update US Income Tax information for 2018. Two forms haven't yet been published. If changes needed, will do in subsequent commit.

[J.Alex Aycinena]

Updated	 via  https://github.com/Gnucash/gnucash/commit/8f4f8a1d (commit)
	from  https://github.com/Gnucash/gnucash/commit/3ab5a2be (commit)



commit 8f4f8a1dc4f1f0c2b7efe805dc510fcd97ae4eba
Author: Alex Aycinena <alex.aycinena at gmail.com>
Date:   Thu Jan 17 12:15:51 2019 -0800

    Update US Income Tax information for 2018. Two forms haven't yet been published. If changes needed, will do in subsequent commit.



Summary of changes:
 libgnucash/tax/us/txf.scm | 146 +++++++++++++++++++++++-----------------------
 1 file changed, 73 insertions(+), 73 deletions(-)