API for datatypes derived from multichan16 (github.com/janelia-flyem/dvid/datatype/multichan16)
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Command-line:

$ dvid node <UUID> <data name> load <V3D raw filename>

    Adds multichannel data to a version node when the server can see the local files ("local")
    or when the server must be sent the files via rpc ("remote").

    Example: 

    $ dvid node 3f8c mydata load local mydata.v3draw

    Arguments:

    UUID          Hexadecimal string with enough characters to uniquely identify a version node.
    data name     Name of data to add.
    filename      Filename of a V3D Raw format file.
	
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HTTP API (Level 2 REST):

GET  <api URL>/node/<UUID>/<data name>/help

	Returns data-specific help message.


GET  <api URL>/node/<UUID>/<data name>/info
POST <api URL>/node/<UUID>/<data name>/info

    Retrieves or puts data properties.

    Example: 

    GET <api URL>/node/3f8c/multichan16/info

    Returns JSON with configuration settings.

    Arguments:

    UUID          Hexadecimal string with enough characters to uniquely identify a version node.
    data name     Name of multichan16 data.


GET  <api URL>/node/<UUID>/<data name>/<dims>/<size>/<offset>[/<format>]
POST <api URL>/node/<UUID>/<data name>/<dims>/<size>/<offset>[/<format>]

    Retrieves or puts orthogonal plane image data to named multichannel 16-bit data.

    Example: 

    GET <api URL>/node/3f8c/mydata2/xy/200,200/0,0,100/jpg:80  (channel 2 of mydata)

    Arguments:

    UUID          Hexadecimal string with enough characters to uniquely identify a version node.
    data name     Name of data.  Optionally add a numerical suffix for the channel number.
    dims          The axes of data extraction in form "i_j_k,..."  Example: "0_2" can be XZ.
                    Slice strings ("xy", "xz", or "yz") are also accepted.
    size          Size in pixels in the format "dx_dy".
    offset        3d coordinate in the format "x_y_z".  Gives coordinate of top upper left voxel.
    format        Valid formats depend on the dimensionality of the request and formats
                    available in server implementation.
                  2D: "png", "jpg" (default: "png")
                    jpg allows lossy quality setting, e.g., "jpg:80"