Add license headers (#16)

Author: odow

src/GDXFile.jl

@@ -1,3 +1,9 @@
+# Copyright (c) 2026 Martin Kirk Bonde, James Daniel Foster and contributors
+# Copyright (c) 2020-2023 GAMS Software GmbH
+#
+# Use of this source code is governed by an MIT-style license that can be found
+# in the LICENSE.md file or at https://opensource.org/licenses/MIT.
+
 # High-level GDX file API for GDXInterface.jl
 
 # =============================================================================

src/GDXInterface.jl

@@ -1,3 +1,9 @@
+# Copyright (c) 2026 Martin Kirk Bonde, James Daniel Foster and contributors
+# Copyright (c) 2020-2023 GAMS Software GmbH
+#
+# Use of this source code is governed by an MIT-style license that can be found
+# in the LICENSE.md file or at https://opensource.org/licenses/MIT.
+
 module GDXInterface
 
 import DataAPI

src/gdx_c_api.jl

@@ -1,3 +1,9 @@
+# Copyright (c) 2026 Martin Kirk Bonde, James Daniel Foster and contributors
+# Copyright (c) 2020-2023 GAMS Software GmbH
+#
+# Use of this source code is governed by an MIT-style license that can be found
+# in the LICENSE.md file or at https://opensource.org/licenses/MIT.
+
 # GDX library bindings (for libgdx)
 # Low-level C API wrappers for reading and writing GDX files
 

test/runtests.jl

@@ -1,3 +1,9 @@
+# Copyright (c) 2026 Martin Kirk Bonde, James Daniel Foster and contributors
+# Copyright (c) 2020-2023 GAMS Software GmbH
+#
+# Use of this source code is governed by an MIT-style license that can be found
+# in the LICENSE.md file or at https://opensource.org/licenses/MIT.
+
 import Test: @testset, @test, @test_throws
 import Tables
 import DataFrames: DataFrame, names, metadata!

test/test_gdxfile.jl

@@ -1,3 +1,9 @@
+# Copyright (c) 2026 Martin Kirk Bonde, James Daniel Foster and contributors
+# Copyright (c) 2020-2023 GAMS Software GmbH
+#
+# Use of this source code is governed by an MIT-style license that can be found
+# in the LICENSE.md file or at https://opensource.org/licenses/MIT.
+
 # Tests for GDXFile API
 
 # For reference: script to create test file "gams_gdx_test.gdx" using GAMS