Log Message:
Update to 0.13.4

* Fix build with boost 1.65.0

Changelog:
2018-02-26  Kohei Yoshida  <kohei.yoshida@gmail.com>  \ 
[ef2e27538e335583ef3ff85c4bc4f512efc72eb5]

	Up the version to 0.13.4.

2018-02-21  Markus Mohrhard  <markus.mohrhard@googlemail.com>  \ 
[13af2fbab2cac1020d6bb840833c0e0efc231bff]

	protect the self-closing xml element code against self-closing root elements

	Found by Antti Levomäki and Christian Jalio from Forcepoint.

	(cherry picked from commit 12e5d89cbd7101c61fbdf063322203a1590a0ef5)

2018-02-19  Kohei Yoshida  <kohei.yoshida@gmail.com>  \ 
[b8848ef7fc6a7d89e3f872574e36cbbab82275b0]

	xls-xml: Gracefully handle formula cells without cached results.

	This fixes #51.

	(cherry picked from commit 32a1b05ffc6edd7d528b6760dab9035252329ab0)