[API] Move sumbodules into separate folder

.gitmodules

@@ -1,9 +1,9 @@
-[submodule "imgui"]
-	path = imgui
+[submodule "include/imgui"]
+	path = include/imgui
 	url = https://github.com/ocornut/imgui
-[submodule "imgui-node-editor"]
-	path = imgui-node-editor
-	url = https://github.com/thedmd/imgui-node-editor.git
-[submodule "imnodes"]
-	path = imnodes
-	url = https://github.com/Nelarius/imnodes.git
+[submodule "include/imgui-node-editor"]
+	path = include/imgui-node-editor
+	url = https://github.com/thedmd/imgui-node-editor
+[submodule "include/imnodes"]
+	path = include/imnodes
+	url = https://github.com/Nelarius/imnodes

buildSrc/src/main/groovy/imgui/generate/GenerateLibs.groovy

@@ -39,12 +39,12 @@ class GenerateLibs extends DefaultTask {
 
         // Copy ImGui h/cpp files
         project.copy { CopySpec spec ->
-            ['imgui', 'imnodes', 'imgui-node-editor'].each {
+            ['include/imgui', 'include/imnodes', 'include/imgui-node-editor'].each {
                 spec.from(project.rootProject.file(it)) { CopySpec s -> s.include('*.h', '*.cpp', '*.inl') }
             }
 
             if (withFreeType) {
-                spec.from(project.rootProject.file('imgui/misc/freetype')) { CopySpec it -> it.include('*.h', '*.cpp') }
+                spec.from(project.rootProject.file('include/imgui/misc/freetype')) { CopySpec it -> it.include('*.h', '*.cpp') }
             }
 
             spec.from(project.rootProject.file('imgui-binding/src/main/native'))