Implemented coned sensors.

[bk2w]

Sensors are able to scan multiple cells if far enough away.
Addresses issue #106

[bk2w]

Sensors include a new BeamWidth parameter that determines the angular width of the sensor beam, and affects how many cells are scanned at each interval. The sensor footprint is calculated based on true altitude, and compared against the size of the cells on the planetary body. This means that a given sensor at a given altitude can scan more cells on Gilly or Pol than on Eve.

This helps make the medium sensor much more appealing, despite its size and power consumption.

On most bodies, the small sensor can only scan one cell at a time. The one exception is Gilly, simply because of it's tiny size. At maximum altitude over Gilly (edge of SOI), the small sensor scans a cluster of 7 cells

The medium sensor is generally able to scan a cluster of multiple cells, but requires altitude to achieve this. At max altitude over Pol (1.042Mm, edge of SOI), the medium sensor can scan a hexagonal cluster of 217 cells 9-cells on a side; this is the largest cluster possible. Max cluster size on Minmus is 169, 8-cells on a side. On Kerbin-sized bodies, the medium sensor can only scan one cell at a time.

The sensor BeamWidths are part.cfg parameters and easily tweaked for balancing.

[bk2w]

An additional factor that might be used for balancing a wide sensor be is increasing the power consumption based on altitude or number of cells that would be scanned.