T copter springy legs

This is a collection of springy legs for the "T" Copter series of multi-copters ([T4 quadcopter](http://www.thingiverse.com/thing:261145) and [T6 hexacopter](http://www.thingiverse.com/thing:246350) and the [Tubular Crossfire](http://www.thingiverse.com/thing:261298)). It combines the long and short legs previously included in those various files.
Also featured is a new "split" mounting design that allows the leg to be replaced without removing the arm from the copter (as requested by @khogan). For the split design slide the two parts together from the side - don't try to clip the upper cap over the lower leg.
See the original [springy leg video here](http://youtu.be/OrY0ApIrMe8).
As always the Sketchup CAD file is included so you can make changes to suit your needs.
**Tip about slicer settings**
I had to set the "minimum infill length" down to 1mm in my slicer settings to get it to fill the small tips on the split legs. Unsure, but that might be important for strength. Asi