Reduce Makefile prints to clean build output

[jjcarstens]

Makefile and CC prints can be useful, but most of the time they are overwhelming especially for non-C programmers. This simplifies the prints.

To re-enable, set V=1 like is common with many Makefile/C projects. For example V=1 make, V=1 mix compile, etc.

==> scenic
 CC line.o
 LD line.so
 CC matrix.o
 LD matrix.so
 CC bitmap.o
 LD bitmap.so
Compiling 84 files (.ex)
Generated scenic app