cache: Get markup_syntax from vimwiki, drop g:taskwiki_markup_syntax

I don't see the point of forcing the user to select this manually in
both vimwiki and taskwiki.

doc/taskwiki.txt

@@ -733,13 +733,6 @@ constructs.
         Example:
         let g:taskwiki_maplocalleader=",t"
 
-*taskwiki_markup_syntax*
-        This variable specifies the markup syntax you want to use in your
-        VimWiki pages. Valid values are "default" and "markdown".
-
-        Example:
-        let g:taskwiki_markup_syntax = "default"
-
 =============================================================================
 9. TROUBLESHOOTING					   *taskwiki-trouble*
 

taskwiki/cache.py

@@ -108,7 +108,7 @@ class TaskCache(object):
         default_rc = util.get_var('taskwiki_taskrc_location') or '~/.taskrc'
         default_data = util.get_var('taskwiki_data_location') or None
         extra_warrior_defs = util.get_var('taskwiki_extra_warriors', {})
-        markup_syntax = util.get_var('taskwiki_markup_syntax') or 'default'
+        markup_syntax = vim.eval("vimwiki#vars#get_wikilocal('syntax')") or 'default'
 
         # Validate markup choice and set it
         if markup_syntax in ["default", "markdown"]:

tests/base.py

@@ -69,8 +69,7 @@ class IntegrationTest(object):
     def configure_global_variables(self):
         self.command('let g:taskwiki_data_location="{0}"'.format(self.dir))
         self.command('let g:taskwiki_taskrc_location="{0}"'.format(self.taskrc_path))
-        self.command('let g:vimwiki_list = [{"syntax": "default", "ext": ".txt","path": "%s"}]' % self.dir)
-        self.command('let g:taskwiki_markup_syntax="{0}"'.format(self.markup))
+        self.command('let g:vimwiki_list = [{"syntax": "%s", "ext": ".txt","path": "%s"}]' % (self.markup, self.dir))
 
     def setup(self):
         assert not self.client