code coverage tool

	$ 6cov -g 235.go 6.out
	235.go:62,62 main·main 0x27c9-0x2829 MOVL	$main·.stringo(SB),AX
	235.go:30,30 main·main 0x2856-0x285e ADDQ	$6c0,SP
	$

and assorted fixes.

R=r
DELTA=743  (732 added, 8 deleted, 3 changed)
OCL=19226
CL=19243
7 files changed
tree: b96e732fcf56ddf56af4ece58fa61e28ba0eb3b2
  1. doc/
  2. include/
  3. lib/
  4. pkg/
  5. src/
  6. test/
  7. usr/