update to godot 3.1.1

See merge request TheExperienceArchitects/Marte/marte-engine!6

Create and upload osx.zip

See merge request TheExperienceArchitects/Marte/marte-engine!5

Enabled osxcross build in ci

See merge request TheExperienceArchitects/Marte/marte-engine!4

Thanks everyone! You're all stars <3

(cherry picked from commit e3b7f9e1)

(cherry picked from commit d93c3548)

(for safe keeping)

This reverts commit 9e2cf9ef.

It caused this regression: 28335.
Fixes #28335.

This reverts commit 4c10a322.

(cherry picked from commit 33a0011a)

(cherry picked from commits f46899e9)
and 479649b5)

This reverts commit 4fda05e1.

(cherry picked from commit 2f3328a0)

This reverts commit 42514bfd.

There is still an unsolved regression from this commit (#28002)
which needs to be addressed before cherry-picking this one.

This reverts commit 24b7f088.

This causes a particles regression in tps-demo

(cherry picked from commit 296c7407)

(cherry picked from commit 8f762aef)

(cherry picked from commit caaa4921)

(cherry picked from commit 42032669)

(cherry picked from commit dee98d3b)

Made AudioFrame and Vector2 equivalent for casting.
Added ability to obtain the playback object from stream players.
Added ability to obtain effect instance from audio server.

(cherry picked from commit e3376474)

(cherry picked from commit 0d41f8fb)

(cherry picked from commit 5f137925)

(cherry picked from commit 8be9fd83)

(cherry picked from commit 8627f151)

(cherry picked from commit 514a3fb9)

(cherry picked from commit 55f3bd97)

(cherry picked from commit cc71fb23)

Adds the following menu options to the Sprite editor: "Convert to Mesh2D", "Convert to Polygon2D", "Create CollisionPolygon2D Sibling" and "Create LightOccluder2D Sibling"

(cherry picked from commit c218c631)

(cherry picked from commit 4a2c4330)

(cherry picked from commit 1f54b11d)

Network peers get_var/put_var
File get_var/store_var
GDScript/Mono/VisualScript bytes2var/var2bytes
Add MultiplayerAPI.allow_object_decoding member which deprecates PacketPeer.allow_object_decoding.

Break ABI compatibaility (API compatibility for GDNative).

(cherry picked from commit 393e62b9)