[CI] Added support for conditional builds and env vars (#1320)

* Changed travis deploy scheme

* Fixed indentation

* Okay NOW I did fix indentation (hopefully)

* Conditional deployment tests

* Fixed a 7:35 AM typo

* Fixed builds not building.

.travis.yml

@@ -1,24 +1,35 @@
 dist: trusty
 language: python
+cache: pip
+notifications:
+  email: false
+
 python:
 - 3.5.3
 - 3.6.1
 install:
 - echo "pytest>3" >> requirements.txt
 - echo "pytest-asyncio" >> requirements.txt
-- echo "git+https://github.com/Rapptz/discord.py.git@rewrite#egg=discord.py[voice]"
-  >> requirements.txt
+- echo "git+https://github.com/Rapptz/discord.py.git@rewrite#egg=discord.py[voice]" >> requirements.txt
 - pip install -r requirements.txt
 - pip install .
 script:
 - python -m compileall ./redbot/cogs
 - python -m pytest
-before_deploy:
-- curl https://artifacts.crowdin.com/repo/GPG-KEY-crowdin | sudo apt-key add -
-- echo "deb https://artifacts.crowdin.com/repo/deb/ /" | sudo tee -a /etc/apt/sources.list
-- sudo apt-get update -qq
-- sudo apt-get install -y crowdin
-deploy:
+
+jobs:
+  include:
+    - stage: Deployment
+      if: tag IS present
+      python: 3.5.3
+      env:
+        - DEPLOYING=true
+      before_deployment:
+      - curl https://artifacts.crowdin.com/repo/GPG-KEY-crowdin | sudo apt-key add -
+      - echo "deb https://artifacts.crowdin.com/repo/deb/ /" | sudo tee -a /etc/apt/sources.list
+      - sudo apt-get update -qq
+      - sudo apt-get install -y crowdin
+      deploy:
         - provider: pypi
           user: Red-DiscordBot
           password:
@@ -37,6 +48,3 @@ deploy:
             branch: V3/develop
             python: 3.5.3
             tags: true
-cache: pip
-notifications:
-  email: false

setup.py

@@ -8,6 +8,7 @@ import sys
 from setuptools import find_packages
 
 IS_TRAVIS = 'TRAVIS' in os.environ
+IS_DEPLOYING = 'DEPLOYING' in os.environ
 
 dep_links = ['https://github.com/Rapptz/discord.py/tarball/rewrite#egg=discord.py-1.0']
 if IS_TRAVIS:
@@ -22,7 +23,7 @@ def get_package_list():
 def get_requirements():
     with open('requirements.txt') as f:
         requirements = f.read().splitlines()
-    if IS_TRAVIS:
+    if IS_TRAVIS and not IS_DEPLOYING:
         requirements.remove('git+https://github.com/Rapptz/discord.py.git@rewrite#egg=discord.py[voice]')
     else:
         requirements.append('discord.py>=1.0.0a0')  # Because RTD