Merge various contributions:

- Updates readme with billing_project mount option.
- Adds billing_project to supported fstab options.
- Allow passing of more debugging options.
- Make stat cache capacity configurable
- Preserve http_proxy environment variable when daemonizing.

Second release built with Golang 1.9.7.

There appears to be a regression betweem Golang 1.9.7 and 1.10.

Add a check to make sure random reads don't read past the end of an o…

…bject.

gcsfuse 0.27.0

* Fix build process.

gcsfuse 0.26.0

* Fixed lint errors.
* Update package build scripts.

Add logic to detect and optimise random reads.

Signed-off-by: Bjorn Leffler <leffler@google.com>

* Optimisations for streaming reads and parallel read access.

Various bug fixes:
* Add support for requester pays.
* Fixes to documentation.
* Fix and clarify certain error messages.

gcsfuse 0.23.0

 *  Move informational logging to stdout. Now stderr contains only actual errors
    encountered when processing fuse requests. See issue GoogleCloudPlatform#242.

 *  Don't fail to mount when the bucket doesn't work. Instead print only an
    error. See issue GoogleCloudPlatform#244.

gcsfuse 0.22.0

 *  Add an `only_dir` fstab option.
 *  Add fstab options for throttling.
 *  Check at program startup that the bucket works properly.
 *  Add cache TTL fstab options.
 *  Update vendored dependencies.
 *  Build with a new version of Go.
     *  This works around a memory usage problem: http://golang.org/issues/20448

gcsfuse 0.21.0

 *  Support `temp_dir`, `uid`, and `gid` in `/etc/fstab`.