[JOSS Review] Bug: Let findFeatures functions also accept files which have lowercase file extension

[hechth]

Similar to when importing the files into the info, the findFeatures functions don't accept lowercase filenames etc. which have an .mzml extension.

> info <- patRoon::generateAnalysisInfo("myvolume")
> features <- patRoon::findFeaturesXCMS3(info)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201001_003-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201001_098-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201009_003-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201009_098-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201016_003-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201016_098-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201021_003-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201021_098-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201202_003-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201202_098-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201209_003-QCstd_POS_MU.mzml] (in myvolume)
Analysis does not exist: Galaxy23-[qc_solvent_centroids__Tribrid_201209_090-QCstd_POS_MU.mzml] (in myvolume)
Error in patRoon::findFeaturesXCMS3(info) : 1 assertions failed:
 * Variable 'x': No analyses found with correct data format (valid: mzXML, mzML).

[rickhelmus]

Alright, the needed code changes for correct case insensitive file extension checking was quite more involving than expected. The commit linked above should handle all cases throughout the workflow now.