Add annotator support

Also adds a bob bio ... root command.

Depends on bob.extension!67 (merged)

bob/bio/base/annotator/Annotator.py

+from bob.bio.base import read_original_data as base_read
+
+
+class Annotator(object):
+    """Annotator class for all annotators. This class is meant to be used in
+    conjunction with the bob bio annotate script.
+
+    Attributes
+    ----------
+    read_original_data : callable
+        A function that loads the samples. The syntax is like
+        :any:`bob.bio.base.read_original_data`.
+    """
+
+    def __init__(self, read_original_data=None, **kwargs):
+        super(Annotator, self).__init__(**kwargs)
+        self.read_original_data = read_original_data or base_read
+
+    def annotate(self, sample, **kwargs):
+        """Annotates a sample and returns annotations in a dictionary.
+
+        Parameters
+        ----------
+        sample : numpy.ndarray
+            The sample that is being annotated.
+        **kwargs
+            The extra arguments that may be passed.
+
+        Returns
+        -------
+        dict
+            A dictionary containing the annotations of the biometric sample. If
+            the program fails to annotate the sample, it should return an empty
+            dictionary.
+        """
+        raise NotImplementedError
+
+    # Alias call to annotate
+    def __call__(self, sample, **kwargs):
+        return self.annotate(sample, **kwargs)