Removed all uses and incudes. Document all includes needed for each file. Added std.scad include.

primitives.scad

@@ -4,8 +4,7 @@
 //   other BOSL2 library shapes and utilities.
 //   To use, add the following lines to the beginning of your file:
 //   ```
-//   include <BOSL2/constants.scad>
-//   use <BOSL2/primitives.scad>
+//   include <BOSL2/std.scad>
 //   ```
 //////////////////////////////////////////////////////////////////////
 
@@ -38,11 +37,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 
-include <constants.scad>
-include <compat.scad>
-use <transforms.scad>
-use <math.scad>
-
 
 // Section: Primitive Shapes