initial formatting changes

replace DOS endings with UNIX endings, and replace leading tabs with
4x spaces in all files. any non-leading tabs (ie, alignment tabs) are
preserved as originally in the files. additionally, a .clang-format has
been committed with the hopes that any new changes past this commit will
be formatted with it

the commands for this change were

dos2unix <files that were using DOS endings>

fd -e c -e h -e cc -e cxx | ag -v CMSIS | \
    while read line; do \
        expand -t4 -i $line > $line.new; mv $line.new $line; \
    done

.clang-format

@@ -0,0 +1,9 @@
+---
+BasedOnStyle: Google
+IndentWidth: 4
+ColumnLimit: 100
+---
+Language: Cpp
+DerivePointerAlignment: false
+PointerAlignment: Left
+...