added stub Contributing file

CONTRIBUTING.md

+To contribute please follow the guidlines detailed below. Thank you!
+
+# file names
+
+- no leading `compass_` whenever possible
+
+# include headers
+
+Include in the following order:
+
+1. The prototype/interface header for this implementation (ie, the .h/.hh file that corresponds to this .cpp/.cc file).
+2. Other headers from the same project, as needed.
+3. Headers from other non-standard, non-system libraries (eg, Qt, Eigen, etc).
+4. Headers from other "almost-standard" libraries (eg, Boost)
+5. Standard C++ headers (eg, iostream, functional, etc)
+6. Standard C headers (eg, cstdint, dirent.h, etc)