remove curvemapper from snlite

[zeffii]

some snlite pruning.

• removing old directive (curvemapper is now a proper node)
  • also removing all associated functions from helper files, they are now part of the curvemapper files.
• adding alternative parsing for required sockets

  """
  >in socketname type   # for required linked sockets  (no default, no nested specification)
  ...etc
  """

  this > is also a hint to the reader that these sockets are necessary for the code to function. Not all script node scripts will need this, but for the scripts you include in json/examples you might want to add this, it also keeps the testing suite happy.

[zeffii]

there are a few ways to do this via the directive, i could be something like these:

i like this, it's really short. , using the less than symbol

>in socketname type   # for required linked sockets

this is more descriptive, so nice for newcomers, but verbose after the first encounter with the concept. academic : /

in socketname type (required)
in socketname type (r)   # shorthand

in these options, you don't need to keep track of renaming sockets.
another option would be

in socketname type
in socketname type
in socketname type
out socketname type
...etc
required=(socketname, socketname.... )

and i sure as hell am not going to be typing that.