Trajectory planner overhaul for lookahead

* Refactored tpRunCycle, tpAddLine, tpAddCircle, and tpAddRigidTap
* Cleaned up const specifiers for many function pointers
* Implemented pass-by-constant pointer for a few large inputs
* Reformatted documentation to be Doxygen compatible
Prototype pass by constant pointer for posemath.

Demonstrates const pointer passing instead of pass-by-value to a few
posemath functions that are used in the trajectory planner.
Added const specifiers and misc fixes.

* Fixed a few more structs passed by value
* Formatting fixes
Draft conversion of pmCartXXX functions to pass by constant pointer

Converted most quaternon functions to pass by constant pointer to constant data

Converted remainder of posemath to use constant pointer to constant value

Fixed pmLineInit

Stripped out remaining PmPose and PmLine references in TP.

An alternative to PmLine was added in PmCartLine, which strips out all
of the rotation information. Because each axis is treated as orthogonal
and linear as far as trajectory planning, there is no use for an
additional rotation term. More complex kinematics are dealt with
external to TP, so there is no need for the extra space and processing.

Minor misc. conversions to pointer input / output
Whitespace fixes
First cut of 3D arc calculation.

This implementation is basically a copy/paste from the octave
scratchwork.

Fixed a bunch of dumb errors

Need to track down init error in Circle init function.
Added debug info and fixed some obvious errors.

The output looks nominally correct for a simple test case.
Working blend arcs with zero final velocity.
Fixed tight corner and small angle case
Added some test NC code for blend comparison.
Fixed typo in teleop data struct
Actually fixed angle edge cases.
Really ugly but working optimization
Added simple segment pruning
Moved verbose debug messages to a macro to allow conditional compiling.
Added cscope to Makefile
added comments and moved velocity max check
Refactored blend stuff into separate function
Fixed a bunch of bugs

* Fixed issue where theta was half of what it should be, causing arcs to be too short.
* Fixed intersection angle bug due to comparing prev_tc to itself.
* Fixed backward walk to be limited in depth. Hard-coded a constant for now, but eventually this should be user-controllable.
* Fixed debug output redundant definitions
Built on 10.04 RTAPI