Fixes #505

It seems some fields were outdated/wrong. Fixes #502

* Addling support for license api endpoint

* Fixing time fields to proper structs

* license.go: giving date fields proper struct type

* license.go: moving 'license' string literal to NewRequest call

* license.go: moving AddLicense function to option struct POST to fall inline with the rest of this package

Sessions is a V3-only API and should no longer be included in this
library.

* Adding missing users fields, updating docs link

* Fixing bad single quote

* runners.go: Adding IPAddress field, updated docs url

* Fixing doc link

* Adding missing users fields, updating docs link

* Fixing bad single quote

* Added WebUrl to Job struct that is provided by the Gitlab API json, but not included in the client Job struct.

* modifed field name to conform to lint preferences

* Revert NotesService and DiscussionsService ISOTime -> time.Time
Signed-off-by: Sune Keller <absukl@almbrand.dk>

* Fix missing imports
Signed-off-by: Sune Keller <absukl@almbrand.dk>

Add Discussions API implementation

* Update list of available access levels

Update list of availabe access levels:
- Change `OwnerPermission` to plural
- Rename `Master` to `Maintainer`, see https://about.gitlab.com/2018/06/22/gitlab-11-0-released/#master-role-renamed-to-maintainer
  for more information

* Update access levels for backwards compatibility

Add option to list inherited project and group members. Updated the
documentation of the existing `ListProjectMembers` and
`ListGroupMembers` functions for clarity.

Fixes #484

* Query encoding should use url.PathEscape

In repository_files.go, url encoding is done with url.QueryEscape, but this makes it impossible to get files with a space in their name. Using url.PathEncodes changes the space encoding from "+" to "%20" and fixes the issue.

* Removed PathEscape when encoding project path

* Fix typos

And extend the MergeEvent struct.

* Add GetProjectLanguages to get languages from a project

* rename example fuction name

* Fix format issues, change type to fit better to the API

* Implemented access requests API

* Update API coverage in Readme.md

* resolve conversation

* added custom attributes

added tests

fixed typo

* Refactored to fit idioms of the package better

refactored methods to be  to have fully named functions

rewrote tests

updated typos and syntax

* fixed typo caught by linter

* refactored per maintainers request

removed blank line

Tick the `Search` box

* Implemented project badges api

* resolve conversation

Additionally updating existing *Options to include:
 - UpdatedAfter/Before - "Return merge requests updated on/before/after the given time"
 - SourceBranch- "Return merge requests with the given source branch"
 - TargetBranch - "Return merge requests with the given target branch"
 - Search - "Search merge requests against their title and description"

Corrected some outdated documentation.

More info here: https://docs.gitlab.com/ce/api/merge_requests.html#list-group-merge-requests

* projects.go: adding approvals_before_merge to CreateProjectOptions

* project.go: updating gitlab api doc ref to reflect change to CreateProjectOptions

* Implement DownloadSingleArtifactsFile

* Fix bad variable name

* Fix function docstring

* Make jobID an int var

* Use QueryEscape for consistency

* Dont escape filepath

* Fix typo

* Add weight field to UpdateIssueOptions struct

* Fix weight field order