Add to monthly doc that reverting is an option

See merge request !1106

[UI] Set textarea resize:vertical by default.

[refactor] Factor out commit list from compare and new MR.

Fix link_to_reply_diff.

Factor issue and MR edit form error list.

Factor error and success methods from services.

cleanup empty repo page

Merge branch 'spinach-step' of https://github.com/cirosantilli/gitlabhq into cirosantilli-spinach-step
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Conflicts:
	features/steps/project/markdown_render.rb

[factor] Prefix Spinach features with Spinach::Features::.

Update highlight.js to 8.2

highlight.js generated using build script `build.py` for all languages.

See merge request !175

7.4 development

Development branch during `master` code freeze for 7.3

See merge request !1096

Monthly release document update

See merge request !1092

Conflicts:
	doc/install/installation.md

Revert sticky headers

See merge request !1104

This reverts commit 6eb85b1a.

Save last scrollposition and scroll back when leaving ZEN mode

improve 7.3 upgrade process & redis setup

update gitlab shell to 1.9.8 for gitlab 7.2.2

Typo it -> its.

formatting improvements to 6.0-to-7.3.md

Fixes
https://github.com/gitlabhq/gitlabhq/commit/2b35c887904b6a7a05a7c88fdf1ccd66ba943e20#commitcomment-7829537,
https://github.com/gitlabhq/gitlabhq/commit/5704e6fee9d2dea67c4a91b43d06a9958484d29b#commitcomment-7829367,
&
https://github.com/gitlabhq/gitlabhq/commit/5704e6fee9d2dea67c4a91b43d06a9958484d29b#commitcomment-7829381

As committed in https://github.com/gitlabhq/gitlabhq/commit/873acfd9aa54e801d5786c32b05c4f8ad21af72a GitLab 7.2.2 requires GitLab Shell 1.9.8. Fixes https://github.com/gitlabhq/gitlabhq/issues/7806.