Add NEO support

[joschaschmiedt]

Neo Containers:

• Block: Main container gathering all the data, whether discrete or continuous, for a given recording session. A block is not necessarily temporally homogeneous, in contrast to Segment.
• Segment: A container for data sharing a common time basis. A Segment is a heterogeneous container for discrete or continuous data sharing a common clock (time basis) but not necessary the same sampling rate, start or end time.
• AnalogSignal: Array of one or more continuous analog signals. A representation of several continuous, analog signals that have the same duration, sampling rate and start time. Basically, it is a 2D array: dim 0 is time, dim 1 is channel index

Mapping between data models:

DH5	NEO
DH5 file	Block
CONT trial (INDEX)	AnalogSignal
TRIALMAP trial	Segment
EV2	Event
TRIALMAP	Epoch, maybe create a class inheriting from Epoch to add stimulus number

From https://neo.readthedocs.io/en/latest/add_file_format.html#recipe-to-develop-an-io-module-for-a-new-data-format

1. Fully understand the object model. If in doubt ask the mailing list_.
2. Fully understand :mod:neo.rawio.examplerawio, which is a fake IO module to explain the API. If in doubt ask the list.
3. Copy/paste examplerawio.py and choose clear file and class names for your IO.
4. implement all methods that raise :class:NotImplementedError in :mod:neo.rawio.baserawio. Return None when the object is not supported (e.g., spikes, waveforms)
5. Write good docstrings. List dependencies, including minimum version numbers.
6. Add your class to :mod:neo.rawio.__init__. Keep imports inside try/except for dependency reasons.
7. Create a class in :file:neo/io/
8. Add your class to :mod:neo.io.__init__. Keep imports inside try/except for dependency reasons.
9. Create an account at https://gin.g-node.org and deposit files in NeuralEnsemble/ephy_testing_data_.
10. Write tests in :file:neo/rawio/test_xxxxxrawio.py.
    You must at least pass the standard tests (inherited from :class:BaseTestRawIO). See :file:test_examplerawio.py
11. Write a similar test in :file:neo.tests/iotests/test_xxxxxio.py. See :file:test_exampleio.py