committing work before reverting line definition.
mainly elliptic curve stuff, fixed dim typesetting,
and maybe added stuff to basics section.
Revert "added inferred definition of a line. should probably double-check this later"

This reverts commit 950bbb743bf0e77827ea6835bbcf33adde7c0824.

Conflicts:
	basics.tex
	main.pdf
added definitions of lines and conics