Added 2D Advection codes
Merge branch 'master' of https://github.com/TedStudley/Advection-Diffusion-Codes

Conflicts:
	Advection/2D/FDM/log
	Advection/2D/FDM/source/advection.cpp
	Advection/2D/FDM/source/main.cpp
Removing unnecessary log file
Merge branch 'master' of https://github.com/TedStudley/Advection-Diffusion-Codes
BDF2 works