Add d3.geo.twoPointEquidistant.
Use internal trig methods.
Fix a bug in hexbin.mesh.
Fix #38 bug in hexbin plugin.
Update keybinding with improvements from iD project

This adds the following:

* Simple disengagement of bindings with .off()
* Allows namespacing of the keybindings
* Proper comment and license notice
Fix occasional NaNs in vanDerGrinten4.
Fix longscroll.js scrollIntoView issue.

This was sometimes causing a positioning/reflow problem in WebKit
browsers.
d3.geo.conicEquidistant: support equal parallels.
d3.geo.conicConformal: support equal parallels.
Add Fahey.
removed traverse
Code formatting.
d3.geo.conic{Conformal,Equidistant}: equator.
Link to Fahey example.
Fix Werner: d3.geo.bonne().parallel(90°).
Add Van der Grinten II and III.
Add Rectangular Polyconic.
Add Times.
Use ε when detecting equirectangular case.
Add Two-Point Azimuthal.