zotonic-tpl-mode: fix for indenting consequtive closing template tags.
(cherry picked from commit 9ba580d5af6628b96238a15ccac805ce56a4b952)
zotonic-tpl-mode: bind C-M-\ to zotonic-tpl-indent-buffer.
(cherry picked from commit da245f4249839d81c0a816255d9af65b63fa5156)
zotonic-tpl-mode: do not treat underscore as being part of a word.
(cherry picked from commit bcb759f0b1fe9cc7d58e5be4fe6fabb871334d24)
zotonic-tpl-mode: add test routines.
(cherry picked from commit 405f7b8e61ce6e8bec367f14ee11fbfe1f8d1ec3)
zotonic-tpl-mode: add testsuite.
(cherry picked from commit b850948277f2c704c78f446aaf6c731eacaa4622)
zotonic-tpl-mode: add test 8.
(cherry picked from commit 87673bd22749a2e3b11c2dd152945996bc176b05)
zotonic-tpl-mode: add test 9.
(cherry picked from commit a8e4934ceb9a2fa82e42e6f445b5e00c407f4231)
zotonic-tpl-mode: indentation fixes.
(cherry picked from commit f30e730384b249021dccce365d5d1ec6b5c66689)
zotonic-tpl-mode: add test 10, to fix a regression.
(cherry picked from commit cd23d473b4351ab994602e03e47cba2860bab3aa)
core: add support for 'optional include' templates.

Fixes issue #471.
(cherry picked from commit 03a01ccd45c77ff52a202a4eb825b1695f8d2966)