Removing Python 2 support and updating dependencies (#17)

* Remove python 2 support
* Updating mysqlclient dependency
* Remove SQL Lock
* Remove SQL Utility
* Remove SQL Step Queue

Author: Carl Sverre

.travis.yml

@@ -1,10 +1,10 @@
-sudo: false
 language: python
-python:
-    - "2.7"
-    - "3.4"
-    - "3.5"
-    - "3.6"
 install: pip install .
 script: python setup.py test
 services: mysql
+python:
+  - "3.4"
+  - "3.5"
+  - "3.6"
+  - "3.7"
+dist: xenial

default.nix

@@ -1,28 +1,11 @@
 with import <nixpkgs> {}; {
-  memsqlPython2Env = stdenv.mkDerivation {
-    name = "memsql-python-env";
-    buildInputs = with python27Packages; [
-      python27Full
-      python27Packages.virtualenv
-      python27Packages.twine
-      mysql55
-      zlib
-      openssl
-    ];
-    shellHook = ''
-      [ -d venv2 ] || virtualenv venv2
-      source venv2/bin/activate
-      pip list  --format freeze | grep MySQL-python==1.2.5 >/dev/null || pip install MySQL-python==1.2.5
-    '';
-  };
-
-  memsqlPython3Env = stdenv.mkDerivation {
+  memsqlPython = stdenv.mkDerivation {
     name = "memsql-python-env";
     buildInputs = with python36Packages; [
       python36Full
       python36Packages.virtualenv
       python36Packages.twine
-      mysql55
+      mysql57
       zlib
       openssl
     ];

memsql/common/database.py

@@ -3,17 +3,13 @@
 import _mysql
 import time
 import operator
-import six
 
 try:
     from _thread import get_ident as _get_ident
 except ImportError:
     from thread import get_ident as _get_ident
 
-if six.PY3:
-    from memsql.common.conversions import CONVERSIONS
-else:
-    from MySQLdb.converters import conversions as CONVERSIONS
+from memsql.common.conversions import CONVERSIONS
 
 MySQLError = _mysql.MySQLError
 OperationalError = _mysql.OperationalError
@@ -302,16 +298,10 @@ def escape_query(query, parameters):
         else:
             assert False, 'not sure what to do with parameters of type %s' % type(parameters)
 
-    return _escape_unicode(query)
-
-def _escape_unicode(param):
-    if not six.PY3 and isinstance(param, unicode):
-        return param.encode('utf-8')
-    return param
+    return query
 
 def _escape(param):
     if isinstance(param, (list, tuple)):
-        param = [_escape_unicode(p) for p in param]
-        return ','.join(_mysql.escape_sequence(param, CONVERSIONS))
+        return ','.join(_mysql.escape(p, CONVERSIONS) for p in param)
     else:
-        return _mysql.escape(_escape_unicode(param), CONVERSIONS)
+        return _mysql.escape(param, CONVERSIONS)