Update CI to use Python 3.5 and switch to Buildkite (#103)

Removes Travis

Author: reivilibre

.gitignore

@@ -7,3 +7,5 @@ __pycache__/
 /dist/
 /_trial_temp/
 /htmlcov/
+.idea/
+.python-version

.travis.yml

@@ -1,5 +1,5 @@
 [tox]
-envlist = packaging, pep8, py27-ldap{0,1,2}
+envlist = packaging, pep8, py35, py36, py37, py38
 
 [testenv]
 deps =
@@ -8,9 +8,7 @@ deps =
     ldaptor
     matrix-synapse
     coverage
-    ldap0: ldap3<1.0
-    ldap1: ldap3>=1.0,<2.0
-    ldap2: ldap3>=2.0
+    ldap3>=2.8
 setenv =
     PYTHONDONTWRITEBYTECODE = no_byte_code
     PYTHONPATH = .
@@ -25,7 +23,7 @@ commands =
 
 [testenv:pep8]
 skip_install = True
-basepython = python2.7
+basepython = python3.5
 deps =
     flake8
 commands = flake8 .