Fix wo clean issue

* add `wo update --mainline`
* move mariadb tweaks into wo

wo/core/download.py

@@ -1,6 +1,6 @@
 """WordOps download core classes."""
 import os
-from requests import get, RequestException
+import requests
 
 from wo.core.logging import Log
 
@@ -11,7 +11,7 @@ class WODownload():
         pass
 
     def download(self, packages):
-        """Download packages, packges must be list in format of
+        """Download packages, packages must be list in format of
         [url, path, package name]"""
         for package in packages:
             url = package[0]
@@ -23,15 +23,31 @@ class WODownload():
                     os.makedirs(directory)
                 Log.info(self, "Downloading {0:20}".format(pkg_name), end=' ')
                 with open(filename, "wb") as out_file:
-                    req = get(url, timeout=(5, 30))
+                    req = requests.get(url, timeout=(5, 30))
                     if req.encoding is None:
                         req.encoding = 'utf-8'
                     out_file.write(req.content)
                 Log.info(self, "{0}".format("[" + Log.ENDC + "Done"
                                             + Log.OKBLUE + "]"))
-            except RequestException as e:
+            except requests.RequestException as e:
                 Log.debug(self, "[{err}]".format(err=str(e.reason)))
                 Log.error(self, "Unable to download file, {0}"
                           .format(filename))
                 return False
         return 0
+
+    def latest_release(self, repository):
+        """Get the latest release number of a GitHub repository.\n
+        repository format should be: \"user/repo\""""
+        try:
+            req = requests.get(
+                'https://api.github.com/repos/{0}/releases/latest'
+                .format(repository),
+                timeout=(5, 30))
+        except requests.RequestException as e:
+            Log.debug(self, str(e))
+            Log.error(self, "Unable to query GitHub API")
+        else:
+            github_json = req.json()
+            github_release = github_json["tag_name"]
+        return github_release