Shrimp Shader Generator FLTK2 GUI (SVN)

Removed topolard2d block from Geometric menu. All coordinates transformations are where under Geometric/Coordinates. Fixed shrimp_conversion.h's transformations. Added missing usage information or extended it, for the remaining blocks. Added UND defaults to matrix function parameter for transform block. Pad type parenting fixed where needed.

Extended and added where missing, usage information for the fractal noise blocks. For the 4D noise types, the 4th dimension variable, that defaults to global variable time, now is accordingly of storage class uniform.
Updated the fractal functions header to reflect this change as well.

Small tweak to shownormals block. Fractals will be next.

Updated conversion blocks, the usage information, as well as the vector/normal/point to color conversion, so that results are in [0,1] range as expected.

Renived blend block, mix() block was updated to operate on all types. Other color blocks tweaked, and had usage information updated.

Tweaked the xml blocks usage information, added where missing. Added workarounds for color type step and smoothstep, since i'm told only PRman supports both float and color types, but available RI specs (3.2.1) mention only float type, so in other renderers it'll operate on a component by component basis.
Removed E and PI number blocks, and replaced them instead by a "Useful constants" block, with the values of E, PI, PI/2, 2PI, 1/PI, as defined in shrimp_helpers.h's symbols.

Fixed some blocks, and changed shrimp_helpers.h so that it now has a symbol named UND, the value of which is meaningless. This is so that xml blocks can have easily a "value" that can be interpreted as non-set, for shadeops that accept optional arguments.

Updated usage information for more blocks.

Tweaked matrix setcomp(), with extra usage info, and added matrix inverse block. In 3delight's case, inverse() is used.

Added legacyframebuffer for Aqsis's entry in the renderers description file.
Updated more blocks, with usage information. Updated area() block to consider strategy, shading or dicing, and added workaround for Aqsis's case, which only supports the area() shadeop with a single argument