wxgui/ceria.cpp: fix bug found by cppcheck (reported by David Binderman)
comment out unused SideBar::select_datasets()
removed unused PlotPane::is_background_white()
change wording in ModelInfoDlg
GUI: added checkbox to Functions > Export Peak Parameters

and minor unrelated cosmetic changes
updated .gitignore
cosmetic changes to suppress a few clang warnings
add request from the ML
modify first line comment in almost all files
style: put '} else' on one line