Implement a basic project manager which lets users add, remove, and reload projects (directories) as well as directly open files in those projects.
Also, clean up some code.
On branch projectMngr, changes to be committed:
	modified:   src/mainwindow.cpp
	modified:   src/mainwindow.h
	modified:   src/mainwindow.ui
	modified:   src/projectitem.cpp
	modified:   src/projectitem.h
	modified:   src/projectmodel.cpp
	modified:   src/projectmodel.h
Apply styling to project manager viewer and clean up code.
On branch projectMngr, changes to be committed:
	modified:   config/themes/defaultTheme.css
	modified:   src/mainwindow.cpp
	modified:   src/projectmodel.cpp