[ticket/12924] Make meta tags self-closing

PHPBB3-12924
[ticket/12924] Remove newlines at the EOF

PHPBB3-12924
Merge pull request #3167 from Senky/ticket/12924

[ticket/12924] Make meta tags self-closing
Merge branch 'develop-ascraeus' into develop

Conflicts:
	phpBB/styles/subsilver2/template/index.htm
	phpBB/styles/subsilver2/template/overall_header.html
	phpBB/styles/subsilver2/template/simple_header.html
	phpBB/styles/subsilver2/template/ucp_pm_viewmessage_print.html
	phpBB/styles/subsilver2/template/viewtopic_print.html
	phpBB/styles/subsilver2/theme/images/index.htm