v2.0.0

Improvements and changes for this release include:

• the ability to aggregate PSDs into a PDF that spans multiple days
• replaces old metric names 'pdf_text' and 'pdf_plot' with a single metric name 'pdf'
• output of the 'pdf' metric is controlled by a new section in the preferences file called 'PDF Preferences' or through the command line
• other changes to the preference file include new output directories for PSD and PDF files and modified default metric aliases. This release is not completely compatible with older preference files.
• PDFs require that PSD text files are available. These can be generated with 'psd_corrected' either prior to or concurrently with 'pdf'.
• the dead_channel_exp metric has been retired from MUSTANG. This release removes this metric from ISPAQ.
• requires R-package IRISMustangMetrics_2.2.0 (included and also available on CRAN)
• fixes bug that affected PSD/PDF output when local RESP files are used
• updates recommended package versions for conda environment install