Converted tabs to spaces; added test.m

1. Earlier versions of this software have been written on a machine where
tab indenting was the norm. So some of the source files had a mix of
tabs and spaces. I did not notice this because I set tabstop=4 in my
.vimrc file. On the other hand, GitHub displays each tab as 8 spaces, so
the source files look messy when viewed from GitHub.

2. I actually forgot to add in test.m, despite the fact that README
referred to it for usage.
Fixed Makefile: eig.cu didn't have includes path

The command for eig.cu did not have the -I option, so when nvcc tries to
compile eig.cu, it couldn't find the header magma.h. The problem was
solved when I added -I$(MAGMA_INC), where $(MAGMA_INC) is the path of
MAGMA headers.