* restructure markup & markdown to prepare for multiple markup languages support

* adjust some functions between markdown and markup

* fix tests

* improve the comments

* Filter inactive users before sending emails or creating browser notifications

Signed-off-by: David Schneiderbauer <dschneiderbauer@gmail.com>

* fix formatting issues

Signed-off-by: David Schneiderbauer <dschneiderbauer@gmail.com>

* included requested changes

Signed-off-by: David Schneiderbauer <dschneiderbauer@gmail.com>

* optimized database queries

* rebasing new master and add tablenames for clarification in xorm queries

* remove escaped quotationmarks using backticks

Signed-off-by: David Schneiderbauer <dschneiderbauer@gmail.com>

* Enable assignee e-mail notification

* Check assignee and doer to avoid self made comment notifications.

* Assignee not always defined

* New method to avoid error when assignee deleted

* Assignee empty check

* Added comment's hashtag to url for mail notifications.

Signed-off-by: Jonas <info@jonasfranz.software>

* Added comment's hashtag to url for mail notifications.
Added explanation to return statement.

Signed-off-by: Jonas <info@jonasfranz.software>

* Added comment's hashtag to url for mail notifications.
Added explanation to return statement + documentation.

Signed-off-by: Jonas <info@jonasfranz.software>

* Added comment's hashtag to url for mail notifications.

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Replacing in-line link generation with HTMLURL. (+gofmt)

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Replaced action-based model with nil-based model. (+gofmt)

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Replaced mailIssueActionToParticipants with mailIssueCommentToParticipants.

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Updating comment for mailIssueCommentToParticipants

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Send notifications to partecipants in issue comments

Closes #1216

Includes test (still failing)

* Do not include "labelers" to participants

Fix test to expect what GetParticipants return

a transaction session was in progress. MailParticipants was failing
silently because of the SQLITE_LOCKED error. Make sure failures in
MailParticipants enter the log, and pass on the transaction context.

issue: let caller pass in database context, and use it
issue_comment: obtain database context to pass to UpdateIssueMentions
issue_comment: log any error from call to MailParticipants
issue_mail: pass on database context to UpdateIssueMentions

* Lint models/release.go

* Lint models/ issue_label, issue_mail & mail.go

- Update import paths from github.com/go-gitea to code.gitea.io
- Fix import path for travis

See https://docs.travis-ci.com/user/languages/go#Go-Import-Path