Added README and screenshot, offline <> TODO list.

README.md

@@ -1,3 +1,26 @@
 # xiew
 
-Encode and decode data as PNG image.
+xiew -- Encode and decode data as PNG image.
+
+- Everything related to my libraries is clean of all warning options on Clang, GCC and Valgrind.
+
+Compile:
+```bash
+$ sh compile.sh
+```
+
+Install:
+```bash
+$ sudo sh install.sh
+```
+
+Use:
+```bash
+$ xiew -e input.ext output.png -- "Encode file as PNG image."
+$ xiew -d input.png output.ext -- "Decode PNG image as file."
+```
+
+This is PNG image "encoding" of file 'xiew.c' as PNG image...
+You can get the original file by decoding it with 'xiew' program.
+
+![screenshot](screenshot.png)