* add missing members of List{,Group,Project}IssuesOptions

* go fmt

* fix golint exit status

* add comments to fix golint complaining

* make go vet verbose

* fix wrong usage of printing

* Improve the way we handle tokens

* Use Go's OAuth2 package (#397)

* Use Go's OAuth2 package

* Pass HTTP client to OAuth2 via context

* Create a basic client with username/password

This client will retrieve an oAuth token using: https://docs.gitlab.com/ce/api/oauth2.html#1-requesting-access-token

* Do not use the libraryVersion in de userAgent

As this never got updated, it did’t have much value (if any).

* Add the Path filter to the ListCommits API

* Add the `all` option to the ListCommits API

* 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…