Reset TEXT dict for parsing next dataset

[machichima]

While parsing the fcs file with multiple datasets in it, I discover that the TET value from the first dataset will persist to the next dataset. For example, my first dataset's TEXT include $FIL but the second does not. However, when using fcsparser.parse(..., data_set=1), I found the metadata output from this contains $FIL, which shouldn't.

In this PR I reset the metadata dict when starting parsing the new dataset

[eyurtsev]

Could you include a test file?

[machichima]

Hi @eyurtsev ,

Thanks for the reply! Below is our test file. You can see two datasets in this file, one for FCS2.0 and the other for FCS3.0. You may have a look at @RATIO_NUMERATOR for example, which exists in FCS2.0 dataset but not in FCS3.0 one.

000035.fcs.zip