add --obs-names and --var-names CLI params (#371)

* add --obs-names and --var-names CLI params

* fix lint

* performance improvements in scanpy engine

* fix lint

* fix typo

* correctly handle sparse formats in diffexp

* fix diffexp and 1d slicing

* diffexp uses t-stat, not pval; clean up arg handling

* make _slice a static method

* revise scanpy tests to match new API

server/app/driver/driver.py

@@ -12,11 +12,11 @@ Sort order for methods
 
 class CXGDriver(metaclass=ABCMeta):
 
-    def __init__(self, data, layout_method=None, diffexp_method=None, max_category_items=100):
+    def __init__(self, data, args):
         self.data = self._load_data(data)
-        self.layout_method = layout_method
-        self.diffexp_method = diffexp_method
-        self.max_category_items = max_category_items
+        self.layout_method = args.layout
+        self.diffexp_method = args.diffexp
+        self.max_category_items = args.max_category_items
         self.cluster = None
 
     @property
@@ -44,14 +44,6 @@ class CXGDriver(metaclass=ABCMeta):
     def _load_data(data):
         pass
 
-    @abstractmethod
-    def cells(self):
-        pass
-
-    @abstractmethod
-    def genes(self):
-        pass
-
     @abstractmethod
     def filter_dataframe(self, filter):
         """