Added ToBoolean to GLCommands.c

Converts the CLIPS boolean value to the GLboolean type.
Reversed the comments on two functions in pcdctfun.c

It looks like the comments for neq and eq were backwards so I swapped them to
make them correct. A silly change but one which brings the code base a little
bit into correctness.
Added a tool to convert defines in gl.h to corresponding C code

This is not a complete tool but is in the process of being written.
Added a rule to strip out blank lines
Added a type field to file-line

I added a rule as well to mark lines that are group headings
Added a new rule to identify #defines

I also modified the blank line remover to remove all lines that haven't been
tagged this makes removal of unnecessary lines even easier
Fixed a bug in merge-three-line-headers

I had put UNKNONW instead of UNKNOWN for one of the templates to match
Fixed an error in merge-three-line-headers

I forgot to rename the contents variable to c in the right hand side of the
rule. This has been corrected
Added rules to look for GLAPI calls
Added support for removing the leading * on three-line-headers
Reactivated unknown file retraction
Added header-span definition support

The idea behind these spans is that the distance between each header represents
a set of GLAPI and #define calls. The idea is to only define header spans that
do not overlap onto other header spans. This makes each span represent a unique
part of the file. Currently, I do not have a way to detecting overlapping spans
but I am working on it.