Ref: https://docs.gitlab.com/ce/api/merge_requests.html#list-project-merge-requests

> Note: the changes_count value in the response is a string, not an integer. This is because when an MR has too many changes to display and store, it will be capped at 1,000. In that case, the API will return the string "1000+" for the changes count.

* + ClosesIssues

* Fixed style
Add err check

* + CreatedAt

* +UpdatedAt

* + TimeStats to issue

* Change TimeStats to existed struct in issues receive

NewRequest() can potentially be called with a
nil value present in []OptionFunc. For example
this code would trigger a panic prior to this
commit:

  _, _, err := git.Users.ModifyUser(event.UserId, options, nil)

Following on to: https://github.com/xanzy/go-gitlab/pull/252

This MR exposes the SnippetsService on the client

- Centralize snippet definition in snippet.go

- Add support for description field on create, update, get for personal and project snippets

Since the response of `GET user/activities` contains a date format (`YYYY-MM-DD`) that cannot be unmarshalled into a `time.Time` automatically, additional logic was added to to cover the un-marshalling of the timestamps:

`UserActivityTime.UnmarshalJSON()`
`UserActivityTime.MarshalJSON()`
`UserActivityTime.IsSet()`

see https://stackoverflow.com/questions/25087960/json-unmarshal-time-that-isnt-in-rfc-3339-format

Thanks @lkysow for spotting these!

Target length for comments is around 80 chars.

* added _links property support in projects api

* support for _links in project api, godoc for Links struct

Project Snippets return `web_url` in the fields. Believe adding it to the struct here should allow us to pick it up.
Ref: https://docs.gitlab.com/ce/api/project_snippets.html

* add support for "Gets a member of a group or project."

* add  GroupMembersService

A user can be either an ID or a name.

And make sure we use the same struct field names as the API does.

add environments support

Add support for running pipeline triggers

typo

Add wikis api