Merge pull request #32 from AlekSi/vet

Fix a small issue found with go vet.
Walk symlink dirs when creating $GOROOT

Fixes #29
Merge branch 'master' of github.com:axw/gocov
Reject non-GOPATH packages

gocov makes many assumptions about packages existing
inside GOPATH (or GOROOT). Attempting to "gocov test"
a program/package not inside GOPATH will lead to
unhelpful error messages.

This change is simply to reject the attempt to test
such a package/program with a more useful error message.

See comments in Issue #30
Add -timeout flag to "gocov test"

Also, pass remaining args through to "go test".
This may need revisiting if we ever want to
support testing multiple packages at once
(without using "...", std, etc.)

Fixes #34
Fix breakage introduced in 83cda1567fe3be4ec91bd71577ef1f85c5ed6070

(Check args are specified before attempting to slice.)
Remove an apparently obsolete TODO comment.

Looks like 83cda1567fe3be4ec91bd71577ef1f85c5ed6070 should have
removed this. At any rate, it appears to me that all test flags are
used.
Handle build tags by adding -tags flag.

Obviously, this means we have to pass -tags down to "go test".
Less obviously, we also have to pass the tags to go/build so it finds
files enabled by custom tags. This required creating a custom build
context instead of using the default.
Merge pull request #36 from gward/master

Handle build tags
Add Greg Ward to AUTHORS
Ensure ancestors of instrumented packages are fully symlinked.

Fixes #37
Fix regression in source symlinking/instrumentation

Oops.

Fixes #37
Eliminate "building out-of-date" warning

Modified gocov test to first run "go test -i",
and then "go test". All flags will be passed
to both invocations; the only difference is
that "-i" will be inserted after "test" on the
first one.

Fixes #39