some cleanup of the strand descriptor structure

  More runtime-system name cleanup

  Tweaking runtime system names

  Split encoding nrrd types into separate file so that we can share it
  across targets.

Compiler changes for output as a nrrd.

  Working on stabilize support

  Added datatype to represent method names.

  merging changes from trunk

  adding outputSzb to strand structure

  Made TreeToCL into a functor parameterized over the translation of variables.
  This allows different clients to have different representations for globals, etc.

  Move shared C codegen support to c-util.

  Use the program name as the default output file name.

  Move OpenCL specific types from clang.sml to cl-target.sml

  Added name field to program representation and switched to smart constructors
  in OpenCL backend

  Working on command-line option support

  Working on compiler support for command-line options

  Working on support for parallel runtime

  Working on parallel runtime

  Working on multiple-target support

  Lots of work on getting the IL invariants right.

  Working on debugging value numbering

  More tweaks to get strand state variables right.

  Lots of tweaking of the variable analysis phase and its use in translating
  Low IL to Tree IL.

  Finish implementing field scaling, addition, and subtraction

  Split code to compile and link C code into its own module.

  Added -rpath flag to linking phase so that dynamic libraries work on Linux

  Fix flag passed to C compiler

  Working on refactoring

  Working on codegen refactoring

  Working on refactoring code generation

  Be more consistent about using functions to build CLang terms (instead of using
  the raw constructors)

  Added codegen support for vector-matrix, matrix-vector, and matrix-matrix
  multiplication

  Use matrix copy when assigning to matrix variables.

  Added matrix subscripting support to code generation

  Added codegen support for creating matrices

  Added lerp as an overloaded function

  Overhaul in the way that the MidIL and LowIL represent tensor types (especially
  for orders > 1).  We still need to deal with the flattening of tensor-value
  construction

  Fixed bug in the C code that gets generated for subscripting vectors

  The C-target now compiles and links the generated C code

  Added subscript for vectors and code generation for Subscript when argument
  is vector.

  Added mechanism for supporting "black box" functions (e.g., sin and sqrt).
  Also added atan2, sqrt, and tan functions to Basis

  Added trace operator for 2x2, 3x3, and 4x4 matrices

  Bug fix: get printing format right for vectors

  Added support for tracking output state variables through ILs and generating
  a print function in the C target.

  Add cast to generated code to avoid warning message

  Switch to compiler-generated initially code.

  Working on generating initially code.  Also changed var and exp types in CTarget to
  be datatypes for better typechecking and documentation.

  More work on supporting initially in code generation

  Adding for loops to C code generator

  Adding for loops to TreeIL to support initially code generation

  Bug fix: the update function was cast to the wrong type

  Fix conversions from float vector to integer vectors

  Fixed bug in code generation for inside test

  Working on missing pieces of code generation

  Streamlined code for real to int conversions

  Working on code generation

  Working on code generation.

  Working on C target and code generation

  Working on code generation

  Working on code generation

  Working on code generation

  Split runtime names and C target types into their own modules.

  Added "allowedInline" function

  Lots of changes to push image info through to the code generator.

  Working on code generation

  Working on code generation

  Debugging code generation

  Working on code generation

  Working on code generation

  Working on code generation

  More work on code generation

  Working on code generation

  Working on code generation

  Working on code generation

  Working on code generation