update README.md with build instructions and some forgotten changes

MAKEFILE

@@ -1,4 +1,4 @@
-target_config = release
+target_config = debug
 
 target_name = dgl
 

README.md

@@ -4,7 +4,7 @@ libDGL is a "retro coding" C library aimed at MS-DOS
 [VGA Mode 13h](https://en.wikipedia.org/wiki/Mode_13h) game development. It is developed with 
 DJGPP with 486 DX2 systems as a baseline target for performance.
 
-The project is developed with Watcom C 10.0b.
+The project is developed with Watcom C 10.0b and Borland Turbo Assembler 4.0.
 
 ### Why?
 
@@ -39,8 +39,33 @@ chock-full of bugs.
 * "Mode 7" like support
 * Custom font loading (BIOS-like format?)
 * Joystick / Gravis GamePad support
+* Input device (keyboard/mouse/joystick) events
 * PC speaker sounds
 * Sound Blaster compatible sound/music
 * Gravis Ultrasound compatible sound/music
 * Sine/cosine lookup table optimizations
 * BMP, LBM, GIF image loading (and saving?)
+* Simple immediate mode GUI
+
+### Building
+
+You can use `WMAKE` to build using the included `MAKEFILE`.
+
+To build the library:
+
+```
+> wmake target_config=debug build           ; debug build
+
+> wmake target_config=release build         ; release build
+```
+
+Will output `DGL.LIB` in the project directory.
+
+To build and run a test program from `TEST.C` using the libDGL sources statically linked:
+
+```
+> wmake run
+
+> wmake debug                               ; run through WD debugger
+```
+