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
Use proper path separators for Display file
fix flash9
add structure assignment optional field test
check abstract cast when unifying OpEq/OpNotEq (closes #2698)
disallow closure creation on abstract inline methods (closes #2767)
added readDouble/readFloat on haxe.io.Bytes
added addString, addFloat, addDouble on haxe.io.BytesBuffer
(Flash9) use real field name to check for overrides (closes #2785)
Merge pull request #2800 from jlegrande/development

Use proper path separators for Display file
Add class_path as include path to hxcpp
added Sys.time() test

Lazy test in relation to :
https://github.com/HaxeFoundation/hxcpp/issues/30
Merge pull request #2819 from Dvergar/development

added Sys.time() test
let's test sys things only on sys targets
move Codegen.concat to Type.concat