Fix some stuff

- Mark mod as compatible
- Change mod description
- Update go version
- Speed up image stitching 2x
- Fix stitching progress bar

.travis.yml

@@ -1,6 +1,6 @@
 language: go
 go: 
-  - "1.14.x"
+  - "1.15.x"
 
 env:
   - GO111MODULE=on

bin/stitch/medianBlendedImage.go

@@ -72,6 +72,14 @@ func (mbi *MedianBlendedImage) At(x, y int) color.Color {
 	return mbi.cachedRow.RGBAAt(x, y)
 }
 
+// Opaque returns whether the image is fully opaque.
+//
+// For more speed and smaller filesizes, MedianBlendedImage will be marked as non-transparent.
+// This will speed up image saving by 2x, as there is no need to iterate over the whole image to find a single non opaque pixel.
+func (mbi *MedianBlendedImage) Opaque() bool {
+	return true
+}
+
 // Progress returns the approximate progress of any process that scans the image from top to bottom.
 func (mbi *MedianBlendedImage) Progress() (value, max int) {
 	size := mbi.Bounds().Size()

compatibility.xml

@@ -0,0 +1,3 @@
+<Mod _format_version="0"
+	version_built_with="4">
+</Mod>

mod.xml

@@ -1,4 +1,4 @@
 <Mod name="MapCapture" 
-	description="This mod screen-captures a large part of the map, and stores the screenshot as image." 
+	description="This mod lets you capture a large part of the world, and store it as image." 
 	request_no_api_restrictions="1">
 </Mod>