MinIO: Feature and bug fix release

## Highlights - Minio now supports [AWS S3 Compatible Server Side Encryption](http://docs.aws.amazon.com/AmazonS3/latest/dev/ServerSideEncryptionCustomerKeys.html) using AES-256-GCM and ChaCha20-Poly1305. [Learn more.]( https://docs.minio.io/docs/how-to-use-minio-s-server-side-encryption-with-aws-cli) - Minio extends [AWS S3 Event Message Structure](http://docs.aws.amazon.com/AmazonS3/latest/dev/notification-content-structure.html) to include user metadata in bucket event notifications for lambda compute usecases. - Simplification of gateway backend registration (**Community Contribution** from @timonwong) - Minio now supports virtual host style URL access to buckets. [Learn more](https://docs.minio.io/docs/minio-server-configuration-guide) - Removed hardcoded Minio Browser prefix `/minio`, allowing reverse proxies to easily route requests. ## Changelog - Improve make and make install messages (#5207) <Aditya Manthramurthy> - gateway-gcs: Close the writer with error in case of any errors. (#5217) <Krishna Srinivas> - Remove checkGCSProjectID() as it needs extra permission setting (#5210) <Krishna Srinivas> - Rename UserDefined to UserMetadata for events (#5206) <Krishna Srinivas> - return AWS compliant error if SSE-C key is wrong (#5203) <Andreas Auernhammer> - Support for ListObjectParts in azure-gateway (#5198) <Krishna Srinivas> - add benchmarks for erasure backend (#5084) <Andreas Auernhammer> - Update getObjectInfo to stat for objects with trailing / (#5179) <Nitish Tiwari> - Return ErrContentSHA256Mismatch when sha256sum is invalid (#5188) <Krishnan Parthasarathi> - Fix ListenBucketNotification deadlock (#5028) <Krishnan Parthasarathi> - Handle Path validation inside the PostPolicy handler (#5192) <Krishna Srinivas> - Remove release scripts for minio. (#5181) <Harshavardhana> - api: CopyObject should return NotImplemented for now (#5183) <Harshavardhana> - Virtual host style S3 requests (#5095) <Krishna Srinivas> - Add public data-types for easier external loading (#5170) <Harshavardhana> - Set Minio user-agent for GCS calls (#5154) <Krishna Srinivas> - Return MethodNotAllowed error in PostPolicyBucketHandler if URL contains object name (#5142) <kannappanr> - Add GetInfo() support for solaris (#5174) <Harshavardhana> - Check for value > 7 days in X-Amz-Expires header. (#5163) <kannappanr> - Fix minio distributed setup to properly work on windows (#5152) <Harshavardhana> - replace SSE-C key derivation scheme (#5168) <Andreas Auernhammer> - Help message should prioritize gateway after server (#5153) <Harshavardhana> - add SSE-C support for HEAD, GET, PUT (#4894) <Andreas Auernhammer> - browser: Remove hardcoding of minioBrowserPrefix=/minio (#5048) <Krishna Srinivas> - Make GCS multipart upload failures S3-compatible (#5138) <Krishnan Parthasarathi> - fix content-sha256 verification for presigned PUT (#5137) <Harshavardhana> - Support conditions for ListMultipartUploads and ListParts (#5130) <Harshavardhana> - Display help when access/secret key is not set (#5132) <kannappanr> - Remove redirectHeaders method (#5120) <Nitish Tiwari> - move credentials as separate package (#5115) <Bala FA> - Remove unused value from retry-storage (#5129) <Harshavardhana> - Update GitHub PR template to include mint tests (#4970) <Nitish Tiwari> - Update sample yaml files to latest release RELEASE.2017-10-27T18-59-02Z (#5127) <Nitish Tiwari> - Bucket policies should use minio-go/pkg/policy instead. (#5090) <Harshavardhana> - Allow event notifications to work without region (#5119) <Harshavardhana> - browser: Return a more descriptive error for HTTP 500 (#5112) <Harshavardhana> - Simplify gateway backend registration (#5111) <Timon Wong> - Add space to error message (#5108) <Frank Wessels>