Added a functionderivate(BIDS, out_path, name, varargin) which exports the files from current BIDS layout into out_path/name folder. In other words exports data into derivatives.

varargin are the query options same as in bids.query, in fact they are passed directly to it.

To do (help needed!):

• Options -- when created derivatives, there a list of usefull options to fine tune, but adding them will make list of parameters to long. Options that I would like to include are below.
• Script add a line to dataset_description a new structure each time it is run. But on the third run it crashes (see below)
• Add version of bids-matlab (does it exists?)
• Optimise the loop on files (see Provide easy way to loop over files as structure #161)
• Copy of derivatives. Actually it supports only full paths in dependencies.* field.
• Copy of participants.tsv and scans.tsv files
• Tests

Options

• unzip -- if true, then zipped files are unzipped
• copy_dependencies -- if true, the files that current file depend on are copied even if they are not explicitely queried
• force -- copy file even if he already exists in output. Mutually exclusve with copy_dependencies to avoid circular copy

Crashes during dataset_description generation:

Error using horzcat
Dimensions of matrices being concatenated are not consistent.

Error in bids.derivate (line 68)
    description.GeneratedBy = [description.GeneratedBy pipeline];