Update releases to support future release uri template

See also:
- bitprophet/releases#54 (original PR by
  @scolby33)
- bitprophet/releases#76 (rebased branch of
  above PR used in this commit)
- Feature request: bitprophet/releases#65

Author: tony

doc/conf.py

@@ -33,6 +33,7 @@
 releases_document_name = "history"
 releases_issue_uri = "https://github.com/tmux-python/libtmux/issues/%s"
 releases_release_uri = "https://github.com/tmux-python/libtmux/tree/v%s"
+releases_future_release_uri = "https://github.com/tmux-python/libtmux/tree/%s"
 
 templates_path = ['_templates']
 

requirements/doc.txt

@@ -1,5 +1,5 @@
 docutils==0.14
-releases==1.5.0
+git+https://github.com/tony/releases.git@future-releases-uri-config#egg=releases
 sphinx==1.7.5
 alagitpull==0.0.21
 sphinxcontrib-napoleon==0.6.1