drop std:: qualifiers on more stl datatypes

We "using namespace std" anywhere we need a std::string or a std::vector.
make DiskInterfaceTest.StatBadPath quiet

Add a flag to temporarily suppress error output.

Fixes issue #281.
adjust the wording in "multiple rules generate X" warning

Ideally we'd detect this at build time and only warn if your build
was affected, but that's hard to do.  (Really we should just abort
when this scenario is detected rather than continuing, but now
users are relying on it.)

Hopefully improves issue #543.
Don't record deps in dry runs.

deps_log() is NULL during dry runs, so this fixes a crash. It also
matches ninja 1.2.0's behavior as far as I can tell.

Fixes issue #551.
keep dry run more similar to normal run
Merge pull request #552 from nico/deps_dryrun

Don't record deps in dry runs.
add a .travis.yml, trying out travis-ci.org
travis: pull in gtest before building
make DepsLogTest actually clean up on teardown

I think I commented this out when tracking down a bug and forgot
to uncomment it.
add a test for truncated deps

This doesn't yet exhibit the full problems with truncation, but it's
a start.
disable SubprocessTest.SetWithLots on travis-ci

We run into fork() limits on their VM.
deps log: recover on truncated entry

If a read fails while reading an entry, truncate the log to the last
successfully read entry.  This prevents corruption when a subsequent
run appends another entry.
fix warning
don't count eof as truncated
Don't crash during deps log recompaction if there's more than one deps entry.

Part of issue #554.
Make sure that recompaction writes a pristine new depslog.

...even if a prior run of DepsLog::Recompact() exited without cleaning
up, for example due to a crash or because someone added a `return true;`
in the middle of the function while debugging.  Or because someone hits
ctrl-c during deps log recompaction.

No test, because I can't think of a way to trigger this scenario
programmatically.

Part of issue #554.
Merge pull request #555 from nico/depscompactcrash

Don't crash during deps log recompaction if there's more than one deps entry.
Merge pull request #556 from nico/unlink

Make sure that recompaction writes a pristine new depslog.
Introduce a Truncate() function that works on POSIX and Windows.

Hopefully fixes the build on Windows.
Merge pull request #558 from nico/buildfix

Introduce a Truncate() function that works on POSIX and Windows.