* Update ListUsersOptions: add provider and createdafter

* Update ListUsersOptions: add order_by and sort

* Add unshare project from group support

* Add tests for share and unshare projects from group

* Change reference to CE doc instead of EE

* Rename UnshareProjectFromGroup to DeleteSharedProjectFromGroup

The GitLab documentation is wrong. The field that gets returned is actually `approvals_left`, not `approvals_missing`. See https://gitlab.com/gitlab-org/gitlab-ee/issues/1118#note_17875041

* ci: add lint stage to keep the code healthy

* fix golint warnings on type comment and Go Names

* fix Go Names even golint not complains

* remove testURL when testing with dynamic opt

* add support for creating releases in tags api

* add support for updating release notes

* Support merged_by and merged_at for merge requests

* add support for a couple of fields on the MergeRequest: `merged_by` and `merged_at`

* format file using gofmt

* Add State and Search to ListMilestonesOptions, change StartDate and
DueDate to *ISOTime types.

* Add group milestones methods

Fixes #366.

Most list functions return array of pointers, not values. Updated for
consistency.

To request on [namespace/project] style

* valid case
* invalid case

* Add ListMergeRequestPipelines

* Code cleanup

* Fix the PipelineEvent struct, with proper sub struct for Runner and correct type for the artifacts_file 'size' field

* Updated tests for changes to PipelineEvent

* Formatting

* Naming

* BuildEvent BuildDuration is a float, not a string

* float64

* Duration is an integer, not a string

* Add search API

* Refactor the SearchService a bit…

Thanks @Lorac 😉

Sorry @Lorac I couldn’t resist 😉

* Revert "Add missing ListOptions to ListLabels (#337)"

This reverts commit ad922c4d.

* Revert "Added Confidential Issue Hook (#343)"

This reverts commit 79bdeb00.

Fixes : #336