Standard eig driver, AV = VΛ, tridiagonal

Modules
	stev: eig, QR iteration
	stevd: eig, divide and conquer
	stevr: eig, MRRR
	stevx: eig, bisection
	pteqr: eig, positive definite tridiagonal
	stebz: eig, Kahan
	sterf: eig, QR iteration
	stedc: eig, divide and conquer
	stegr: eig, bisection, see stemr
	stein: eig, inverse iteration
	stemr: eig, relatively robust representation (RRR)
	steqr: eig, QR iteration
	lagtf: LU factor of (T - λI)
	lagts: LU solve of (T - λI) x = y

Detailed Description