partially done work on total source tree rework, separation of engine context and game context, generalization of renderer for different backends as well as web platform target

docs/source_directory_structure.txt

@@ -0,0 +1,20 @@
+all source files are prefixed with 'twn_'
+
+things are categorized into two main folders:
+- 'include' for any definition that are usable from townengine library
+- 'src' for any private implementations
+
+internal headers have '_c.h' ending, so to not collide with our include style
+
+example of a module:
+src/twn_module.c -- internal implementations
+src/twn_module_c.h -- private declarations
+include/twn_module.h -- public declarations
+
+both private and public headers are included via root:
+#include "twn_module.h"
+#include "twn_module_c.h"
+
+additional subfolders in src/ are possible when implementation permutations are in place, build system will chose the appropriate ones
+
+all procedures in include/ headers must have TWN_API macro applied