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Adds working gsl_deriv_central, gsl_deriv_forward, gsl_deriv_backward methods
Translates Section 28.2 Examples in GSL docs
Update README.md
Fixes gsl_ran_dir_2d
Provides roots (of polynomials)
Improved error handling

Turns off default GSL error handler so that it doesn't crash Julia when an error happens. Instead, throws a GSL_ERROR

Newly generated wrappers also catch errors and throws GSL_ERROR when appropriate.
use GSL_ERROR
Improved wrapper generator

Has some heuristics for guessing what outputs are needed and specifying & on the ccall line
Fixes generation of gsl_rand_dir_2d*
extends roots() to optionally do real roots only
Updated documentation for roots
Renamed example files
Cleans up ampersands
Fixes regression in wrappers
Improved wrapper

Now attempts to dynamically allocate returned variables which are passed by reference to C function
Refines heuristic to exclude gsl_*_free()

Add functioning Example 8.2

Add nonfunctioning Example 39
Updated wrappers