First $near commit.

Workaround for weird $near + $maxDistance syntax.
Simplest possible implementation of $near. Still no sorting
In minimongo selector compilation pass along the whole selector and original cursor when possible.

So this information can be used by weird operators such as $near or $.
Some docs.
Naming unused param as '_' wasn't the best idea.
Pass the whole doc and the neighbor operators around in minimongo selector matchers.

So various operators can look up what is the doc they are matching
Sort takes into consideration the distance from given point on $near queries.
EnsureIndex accepts 2d or 2dsphere options to understand what user wants in minimongo.
GeoJSON Utils package.

Not sure if it is good enough, let's see in later tests.
Comment on constant in distance calculations.
Imply GeoJSON Utils package and use it to calculate distance between geojson objects.
Fix package's description
Calculation method by default is 2d
A lot of generated tests to actually make sure distance is correct.
Proved to have working api for 2dsphere.
Let _compileSort handle empty sorting rules. So the line that says: "sort by distance by default" will work
Don't mess the sorting unless it's a geo query
More tests. And weakly depend, not imply!
Touch History.md
Don't have to ensure index to distinguish 2d vs 2dsphere queries.