README is out of date after most recent changes

[TomHogervorst]

The README currently does not document the updated ways in which trace(Set) parameter maps can be used. Information about the default trace set parameter map and the automatic creation of the trace parameter definitions also needs to be included in the file.

[dsimonovic]

Following piece of code in README.md is a non-working piece of code, it is not self contained. No examples of how to create FileEngine type trs file.

import trsfile

with \
	trsfile.open(
		'trace-set',                  # Previously create trace set
		'r',                          # Read only mode
		engine='FileEngine'           # Using the FileEngine
	) as traces, \
	trsfile.open(                     # Note: TrsEngine is the default
		'trace-set.trs',              # Name of the new trace set
		'w',                          # Write mode
		headers=traces.get_headers()  # Copy the headers
	) as new_traces:
	new_traces.extend(traces)         # Extend the new trace set with the
	                                  # traces from the old trace set

[dsimonovic]

The most important example missing in the README.md is how to open trs file, do some simple signal processing, and save to a new file. I would say this piece of code should do, but I am not familiar enough with the library to be sure this is the proper way:

with trsfile.open('input.trs', 'r') as traceset_in:
    headers_clean = traceset_in.get_headers().copy()
    headers_clean.pop(Header.NUMBER_TRACES, None)
    headers_clean.pop(Header.TRACE_SET_PARAMETERS, None)
​
    with trsfile.open('output.trs', 'w', headers=headers_clean) as traceset_out:
        for trace in traceset_in:           
            processed_array = 0.5*trace.samples
            traceset_out.append(Trace(
                    SampleCoding.FLOAT,
                    processed_array,
                    trace.parameters)
            )