s/Connection/Noodle/g
s/ConnectionTest/NoodleTest/g
add missing change for s/Connection/Noodle/g
s/Noodles/Graph/g
s/NoodlesTest/GraphTest/g
invent all.h to reduce class header clutter
create subclasses of std::runtime_error for graph errors
fix PCH breakage
consolidate namespace stuff in all.h