Merge branch '3.1.x'
* 3.1.x: (21 commits)
Added docs for js linting
Fix section how to request events
By huge messy tables
Forgot one
Fix additional back tick
Fix line length
Use note directive
WARNING: toctree contains reference to nonexisting document u'update/index'
Fix VSE comments
Add docs about migrations
tell travis which branches to build
Install sphinx and deps with pip (python lang so no sudo)
Add basic travis config to make docs
Move the mod>ext to extensions
Fix comments from VSE
Add documentation for testing
Fix comments from VSE and line wrap
Add Using_the_phpBB3.0_Language_System
Add https://wiki.phpbb.com/Plural_Rules to doc
Add coding guidelines
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