Added some information and documentation

CONTRIBUTING.md

+
+# Contributing
+Please do :-) Just ask or make a merge request!
+
+
+# How it works
+
+here is a loose graph of the dependencies: handy-moodle.c contains the `main` function
+```
+    handy-moodle.c
+        |
+    gui-window.c----------------->|
+        |                         |
+    gui-course.c----------------->|  
+        |                         |
+    gui-week.c                    |
+        |                         |
+    gui-downloadable-file.c ----->|
+                                  |
+                               moodle.c
+                                  |
+                               moodle-parser.c
+```
+
+0. The main opens a new window;
+1. The window requests its courses to the moodle provider, creates its gui-courses.
+2. Every gui-course request the course content to the moodle provider, and gives the whole info to the children.
+3. Each gui-downloadable-file can request his file to the moodle provider.
+
+Inside the moodle provider all but the init function are async currently.

README.md

+
+#[Insert software name here!]
+
+This software is in pre-alpha: it is not usable yet.
+In the current state, you must add your password manually
+to the system password manager and you can odly download
+only one file most of the time.
+
+##Features
+###Cache
+There is a cache system, but it currently uses the build dir
+and must be activated either always or never at compile time
+(see `CACHING` in config.h). For now, this is a feature used
+(and usable) for development purpose only; and it doesn't work
+with files, yet.
+
+##Future Work
+There is an awful lot to do: cleanup, making use of GLib's GTask,
+intelligent use of cache, an ability to read files inside folders,
+adding support for the courses we don't find the ul in, etc.
+
+See [CONTRIBUTING.md] for informations on how it currently works