[ticket/12132] Add viewtopic_print_head_append event to subsilver2

PHPBB3-12132
[ticket/12132] Add the event to events.md doc

PHPBB3-12132
[ticket/12134] Add ucp_pm_viewmessage_print_head_append event to subsilver2

PHPBB3-12134
[ticket/12180] Add "Each file MUST end with exactly one newline character" rule

PHPBB3-12180
[ticket/12184] Fix undefined variable tpl_fields in profile field manager

PHPBB3-12184
Merge pull request #2026 from nickvergessen/ticket/12184

[ticket/12184] Fix undefined variable tpl_fields in profile field manager

* nickvergessen/ticket/12184:
  [ticket/12184] Fix undefined variable tpl_fields in profile field manager
Merge remote-tracking branch 'bantu/ticket/12180' into develop

* bantu/ticket/12180:
  [ticket/12180] Add "Each file MUST end with exactly one newline character" rule
Merge remote-tracking branch 'vinny/ticket/12132' into develop

* vinny/ticket/12132:
  [ticket/12132] Add the event to events.md doc
  [ticket/12132] Add viewtopic_print_head_append event to subsilver2
Merge remote-tracking branch 'vinny/ticket/12134' into develop

* vinny/ticket/12134:
  [ticket/12134] Add ucp_pm_viewmessage_print_head_append event to subsilver2
[ticket/12188] Add php 5.6 to travis enviroments

PHPBB3-12188
Merge remote-tracking branch 'github-nickvergessen/ticket/12188' into develop-olympus

* github-nickvergessen/ticket/12188:
  [ticket/12188] Add php 5.6 to travis enviroments
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/12188] Add php 5.6 to travis enviroments

Conflicts:
	.travis.yml