Add examples and clean up some stuff

package.lisp

@@ -1,4 +1,6 @@
 (defpackage :cl-quantum/math
+  (:documentation "Basic linear algebra subroutines used to implement the
+quantum operators.")
   (:use :cl)
   (:export #:domatrix
            #:mapmatrix
@@ -47,8 +49,10 @@
            #:vector=))
 
 (defpackage :cl-quantum/state
+  (:documentation "Functions for creating and applying quantum gates.")
   (:use :cl :cl-quantum/math)
-  (:export #:+unset-projector+
+  (:export #:define-constant
+           #:+unset-projector+
            #:+set-projector+
            #:+identity-2x2+
            #:+pauli-x-gate+
@@ -65,6 +69,7 @@
            #:normalize-state
            #:nnormalize-state
            #:state-bits
+           #:make-zero-state
            #:make-normal-state
            #:make-uniform-normal-state
            #:bit-unset-index
@@ -76,12 +81,16 @@
            #:collapse
            #:make-operator
            #:make-controlled-operator
-           #:apply-operator
-           #:napply-operator
-           #:apply-controlled-operator
-           #:napply-controlled-operator))
+           #:make-n-toffoli-operator
+           #:make-n-controlled-z-operator
+           #:replace-state
+           #:apply-gate
+           #:napply-gate
+           #:apply-controlled-gate
+           #:napply-controlled-gate))
 
 (defpackage :cl-quantum/circuit
+  (:documentation "High-level interface for building quantum circuits.")
   (:use :cl :cl-quantum/math :cl-quantum/state)
   (:export #:*circuit-measure-places*
            #:*circuit-operators*
@@ -91,6 +100,7 @@
            #:run-circuit))
 
 (defpackage :cl-quantum/pprint
+  (:documentation "High-level interface for building quantum circuits.")
   (:use :cl :cl-quantum/math :cl-quantum/state)
   (:export #:pprint-complex
            #:pprint-format-bits