Bug fix in BaseAnnotationParser._add() method

for multitrack annotation, make sure a None track does not erase
previously added track.
.mdtm files may contain multitrack annotations
REPEREParser now inherits from BaseTextualAnnotationParser
Added .reset() method to Base{Timeline | Annotation}Parser
SEGParser now inherits from BaseTextualAnnotationParser
from pyannote.parser import SEGParser
Moved feature file parsers to new module pyannote.parser.feature
pyannote.parser documentation (WIP)
Comments
Remove debug print
BaseTextual{Timeline | Annotation}Parser method .read() returns self

Allows chaining such as :
parser = Parser().read(…)
LabelMatrix.arg{max | min} now closer to np.arg{max | min} behavior
BaseAgglomerativeClustering WIP
LabelMatrix update

* added support for del M[ _ , : ] and del M[ : , _ ]
* added support for M[ _ , : ] and M[ : , _ ]
pyannote.algorithm.{helper ==> util}.bic.py

* updated Gaussian class for sklearn 0.11
New tagging algorithm DirectTagger
Documentation for DirectTagger
Bug fix in IdentificationErrorRate

(forgot to update it when Annotation/Timeline API changed)
New BaseAgglomerativeClustering class for clustering algorithms
pyannote.algorithm.{diarization ==> clustering}