Document the challenges and the solutions chosen

doc/README.md

+Building RTEMS applications using EDISOFT/OAR
+=============================================
+
+This document explains in detaill the technical challenges that drove
+the creation of the sample Makefiles in this repository.
+
+Note that you don't need to know these details to create your applications;
+but if you want to know why the Makefiles are structured the way they are,
+and what the options used mean, this document sheds light into the issues
+that forced the specific choices.
+
+## The native FPU challenges - and how to cope
+
+TBD
+
+## Differences between your API invocations across EDISOFT / OAR
+
+TBD
+
+## Link suggestions
+
+TBD