Started work on data interpolation using gsll

This is a temporary commit of work in progress
Added column interpolation via gsll, other minor cleanups

New file contains new classes and methods for column interpolation
This will need to be cleaned up

There are other minor changes.  See ChangeLog
More owrk on table-queries.  Not fully completet
Finished table-queries and other minor mods
Added acceleration slot to interpolation.  Other minor fixes

See ChangeLog for details
First version of column fitting.  Passes initial tests
Added GSLL's nonlinear fitting example as a unit test.

The code and documentation still need to be tweaked and firmed up.  But things seem to be working
Added sigma handling and documentation
Multiple modifications.  Software is now in a fragile state

- Started adding documentation via TINAA
- Renamed several functions, and removed many slot accessors
as these slots are private
- Changed interface to some functions, added new accessor functions.

See ChangeLog file
Fixed remaining errors, all tests pass

I can now resume improving the user interface, adding
documentation, and providing a test example
Added COPYRIGHT

I am using the MIT license obtained from opensource.org/licenses/MIT
Added basic table read and examples.  Expanded matching functions ability
Added least-squares fitting, and other minor fixes

See ChangeLog file
New class structure for column-schema

All tests pass.  Next tasks are
- ensure table building works for foreign-column
- ensure tablel selection works for foreign-column
Adapted to handle foreign arrays

All tests pass.  Handling of foreign arrays lightly tested.  Still need to test table queries with foreign arrays
Fixed errors in respect to foreign-arrays.

I used the example files inthe user directory to exercise the code
It now behaves as it should in regard to table building and querying for
both native and foreign arrays.

I need to exercise the fitting and interpolation code next
Fixing fitting code

Added examples with linear fitting, and fixed errors in code.
Had to disable interpolation because of conflicting slots.

Next step is to unify interpolation and fitting
Fixed interpolation and other minor changes

First cut of interpolation class structure.  This could be improved.

All tests pass
Reworked clss structure for interpolation and added all of GSLL's interpolations

I defined a tree of classes to describe GSLL's interpolation facilities.
This allowed me to simplify the code and move from imperative to declarative
(I think)
All tests pass.  But I did not check all the interpolation methods.
Cleaned up examples, other code, and added `in' query

The examples are cleaner and more informative.  Found and fixed
bugs in code.  Added the `in' query.  Looks like it works.