nicer printing of fields via statically-built printf

scala perf is kif-kif:
real  1m26.564s
user  1m22.504s
sys   0m1.799s

c generation has a bug of double-escaped "\n" -- is it a
Scala-Virtualized C codegen issue?
correct escaping of escaped newline from 7d8b5ce9d8ac40f8297bceafaf9096ca18e9c6f1
reduce c compilation errors

to get towards compilation (still not running). remaining errors are due
to infix_HashCode:

cc -O3 -w query_t5hc.check.c
query_t5hc.check.c:39:23: error: expected identifier
    int64_t x30 = x22.##;
                      ^
query_t5hc.check.c:81:23: error: expected identifier
    int64_t x70 = x67.##;
                      ^
2 errors generated.
create type for rep of a field, now just rep of a string... might be easier for now to impl hash code in c
just use a ops trait for hascode, ToString is provided by LMS in ObjectOps. first step. next step is implementing hashcode so that codegen is good for c too
fixing hashcode from unchecked to usual op, almost there for c compilation
hash function comment
Merge branch 'master' of https://github.com/scala-lms/tutorials