Extract math and hyperbolic functions.

Also, add missing geo/projection/index.js file.

geo/projection/august.js

@@ -1,4 +1,5 @@
 import "projection";
+import "hyperbolic";
 
 function august(λ, φ) {
   var tanφ = Math.tan(φ / 2),

geo/projection/elliptic.js

@@ -1,4 +1,5 @@
-import "projection";
+import "math";
+import "hyperbolic";
 
 // Returns [sn, cn, dn](u + iv|m).
 function ellipticJi(u, v, m) {

geo/projection/hyperbolic.js

@@ -0,0 +1,22 @@
+import "math";
+
+function tanh(x) {
+  x = Math.exp(2 * x);
+  return (x - 1) / (x + 1);
+}
+
+function sinh(x) {
+  return .5 * (Math.exp(x) - Math.exp(-x));
+}
+
+function cosh(x) {
+  return .5 * (Math.exp(x) + Math.exp(-x));
+}
+
+function arsinh(x) {
+  return Math.log(x + asqrt(x * x + 1));
+}
+
+function arcosh(x) {
+  return Math.log(x + asqrt(x * x - 1));
+}

geo/projection/index.js

@@ -0,0 +1,69 @@
+import "start";
+import "quincuncial";
+import "interrupt";
+import "aitoff";
+import "guyou";
+import "mollweide";
+import "sinusoidal";
+import "sinu-mollweide";
+import "armadillo";
+import "august";
+import "baker";
+import "berghaus";
+import "boggs";
+import "bonne";
+import "bromley";
+import "collignon";
+import "conic-conformal";
+import "conic-equal-area";
+import "conic-equidistant";
+import "craig";
+import "craster";
+import "cylindrical-equal-area";
+import "eckert1";
+import "eckert2";
+import "eckert3";
+import "eckert4";
+import "eckert5";
+import "eckert6";
+import "eisenlohr";
+import "fahey";
+import "gringorten";
+import "hammer-retroazimuthal";
+import "hammer";
+import "hatano";
+import "healpix";
+import "hill";
+import "homolosine";
+import "kavrayskiy7";
+import "lagrange";
+import "larrivee";
+import "laskowski";
+import "littrow";
+import "loximuthal";
+import "miller";
+import "modified-stereographic";
+import "mt-flat-polar-parabolic";
+import "mt-flat-polar-quartic";
+import "mt-flat-polar-sinusoidal";
+import "natural-earth";
+import "nell-hammer";
+import "peirce-quincuncial";
+import "polyconic";
+import "rectangular-polyconic";
+import "robinson";
+import "satellite";
+import "times";
+import "transverse-mercator";
+import "two-point-azimuthal";
+import "two-point-equidistant";
+import "van-der-grinten";
+import "van-der-grinten2";
+import "van-der-grinten3";
+import "van-der-grinten4";
+import "wagner4";
+import "wagner6";
+import "wagner7";
+import "wiechel";
+import "winkel3";
+import "end";

geo/projection/math.js

@@ -0,0 +1,26 @@
+var ε = 1e-6,
+    ε2 = ε * ε,
+    π = Math.PI,
+    sqrtπ = Math.sqrt(π),
+    radians = π / 180,
+    degrees = 180 / π;
+
+function sinci(x) {
+  return x ? x / Math.sin(x) : 1;
+}
+
+function sgn(x) {
+  return x > 0 ? 1 : x < 0 ? -1 : 0;
+}
+
+function asin(x) {
+  return x > 1 ? π / 2 : x < -1 ? -π / 2 : Math.asin(x);
+}
+
+function acos(x) {
+  return x > 1 ? 0 : x < -1 ? π : Math.acos(x);
+}
+
+function asqrt(x) {
+  return x > 0 ? Math.sqrt(x) : 0;
+}

geo/projection/projection.js

@@ -1,50 +1,4 @@
-var ε = 1e-6,
-    ε2 = ε * ε,
-    π = Math.PI,
-    sqrtπ = Math.sqrt(π),
-    radians = π / 180,
-    degrees = 180 / π;
+import "math";
 
 var projection = d3.geo.projection,
     projectionMutator = d3.geo.projectionMutator;
-
-function sinci(x) {
-  return x ? x / Math.sin(x) : 1;
-}
-
-function sgn(x) {
-  return x > 0 ? 1 : x < 0 ? -1 : 0;
-}
-
-function asqrt(x) {
-  return x > 0 ? Math.sqrt(x) : 0;
-}
-
-function asin(x) {
-  return x > 1 ? π / 2 : x < -1 ? -π / 2 : Math.asin(x);
-}
-
-function acos(x) {
-  return x > 1 ? 0 : x < -1 ? π : Math.acos(x);
-}
-
-function tanh(x) {
-  x = Math.exp(2 * x);
-  return (x - 1) / (x + 1);
-}
-
-function sinh(x) {
-  return .5 * (Math.exp(x) - Math.exp(-x));
-}
-
-function cosh(x) {
-  return .5 * (Math.exp(x) + Math.exp(-x));
-}
-
-function arsinh(x) {
-  return Math.log(x + asqrt(x * x + 1));
-}
-
-function arcosh(x) {
-  return Math.log(x + asqrt(x * x - 1));
-}

geo/projection/transverse-mercator.js

@@ -1,4 +1,5 @@
 import "projection";
+import "hyperbolic";
 
 function transverseMercator(λ, φ) {
   var B = Math.cos(φ) * Math.sin(λ);