Update year of copyright notices and fix typo (#46)

* Update year of copyright notices

And add missing license information to image_exporter.c

* Fix typo ("immedite")

LICENSE

@@ -1,6 +1,6 @@
 zlib License
 	
-Copyright (c) 2014-2017 Ramon Santamaria (@raysan5)
+Copyright (c) 2014-2019 Ramon Santamaria (@raysan5)
 
 This software is provided "as-is", without any express or implied warranty. In no event 
 will the authors be held liable for any damages arising from the use of this software.

examples/controls_test_suite/controls_test_suite.c

@@ -19,7 +19,7 @@
 *
 *   LICENSE: zlib/libpng
 *
-*   Copyright (c) 2018 raylib technologies (@raylibtech)
+*   Copyright (c) 2019 raylib technologies (@raylibtech)
 *
 **********************************************************************************************/
 

examples/image_exporter/image_exporter.c

@@ -9,7 +9,9 @@
 *   COMPILATION (Windows - MinGW):
 *       gcc -o $(NAME_PART).exe $(FILE_NAME) -I../../src -lraylib -lopengl32 -lgdi32 -std=c99
 *
-*   Copyright (c) 2018 raylib technologies (@raylibtech)
+*   LICENSE: zlib/libpng
+*
+*   Copyright (c) 2019 raylib technologies (@raylibtech)
 *
 ********************************************************************************************/
 

examples/image_raw_importer/image_raw_importer.c

@@ -11,7 +11,7 @@
 *
 *   LICENSE: zlib/libpng
 *
-*   Copyright (c) 2018 raylib technologies (@raylibtech)
+*   Copyright (c) 2019 raylib technologies (@raylibtech)
 *
 **********************************************************************************************/
 

examples/portable_window/portable_window.c

@@ -11,7 +11,7 @@
 *
 *   LICENSE: zlib/libpng
 *
-*   Copyright (c) 2018 raylib technologies (@raylibtech)
+*   Copyright (c) 2019 raylib technologies (@raylibtech)
 *
 **********************************************************************************************/
 

src/raygui.h

@@ -1,6 +1,6 @@
 /*******************************************************************************************
 *
-*   raygui v2.5 - A simple and easy-to-use immedite-mode-gui library
+*   raygui v2.5 - A simple and easy-to-use immediate-mode-gui library
 *
 *   DESCRIPTION:
 *