Move all the motors stuff into a saner namespace

Letting the mechanical engineers name software is never a good idea...

Change-Id: I5d0e43d84a8f45693435472cc0e5e288f6190b14
diff --git a/motors/math.cc b/motors/math.cc
index 291ca43..8441e97 100644
--- a/motors/math.cc
+++ b/motors/math.cc
@@ -3,7 +3,7 @@
 #include <math.h>
 
 namespace frc971 {
-namespace salsa {
+namespace motors {
 namespace math_internal {
 
 float sin_int_table[SinCosTableSize()];
@@ -33,5 +33,5 @@
   }
 }
 
-}  // namespace salsa
+}  // namespace motors
 }  // namespace frc971