desispec 0.16.0

• Small fixes to desi_qa_prod and qa_prod
• Removes a number of QL metrics from offline qa
• Fixes integration tests for desisim newexp refactor
• Removes spectra grouping by brick; nside=64 healpix grouping default
• Add get_nights method to io.meta (PR #422)
• Add search_for_framefile method to io.frame (PR #422)
• Add desi_qa_frame script to generate frame QA (PR #424)
• Add frame_meta to parameters (for slurping the Frame headers) (PR #425)
• Add get_reduced_frames() method to io.meta (PR #425)
• Modifies QA_Prod meta file output to be JSON (PR #425)
• Add load_meta() method to QA_Exposure (PR #425)
• Add time_series ploting to desi_qa_prod (PR #425)
• Add several new plots for skysub residuals (PR #425)
• Adds method to generate QA Table for Prod (PR #425)
• Refactor of skysubresid script (PR #425)
• Refactor QA files to sit in their own folder tree (PR #429)
• Generate HTML files with links to QA figures (PR #429)
• Enable generation of Exposure level QA (PR #429)
• Normalize fiberflat QA by fiber area (PR #429)
• Fixed exptime in fluxcalib ZP calculation (PR #429)
• Added find_exposure_night() method (PR #429)
• Add MED_SKY metric to QA and bright/dark flag in desi_qa_prod
• Update pipeline code for specex and redrock (PR #439 and #440)
• Adds code for adjusting trace locations to match sky lines (PR #433)
• Updates to DB loading (PR #431)
• Adds pixelflat code (PR #426)