Merge pull request #2704 from HaxeFoundation/development

3.1.0
set changes.txt date
Merge pull request #2707 from HaxeFoundation/development

3.1.0 hotfix
Update README.md
Merge pull request #2761 from HaxeFoundation/development

3.1.1
update release-checklist.txt
fix ' haxe.Template can't parse "$$a($$b(a, b))" ' and add tests
Use proper path separators for Display file
ignore visibility for abstract OpAssignOp operations (closes #2810)
do not lie about exhaustive patterns (closes #2809)
add Sys.print/ln with UTF8 printing and use it from Log.trace
hackily escape __b to deal with haxe.Utf8 issue
add sys.FileSystem dummy with implementations for exists and isDirectory
use Js implementation on haxe.io.Input
temp core compiler fix for optional structure field error
serialize resources
comment weird Int tests for now
use python 3.3
that didn't work so well
doc/LICENSE.txt => extra/LICENSE.txt