Basic Makefile
Basic function base class
Temporarily comment out std::to_string()

FIXME: Compilation fails, maybe a GCC bug.

function.cxx: In member function ‘void function::set_param(unsigned int, double)’:
function.cxx:16:10: error: ‘to_string’ is not a member of ‘std’
        + std::to_string(_num));
Add tests for function
Always use C++11
Fixes 35a7160 (needs C++11)

Need to enable C++11 to use std::to_string()
Clean-up
Makefile clean target
Add const qualifiers
Rewrite function class

TODO: tests not updated
variable class
A utilities to create functions
Change function_base interface
function copy constructor
Update test_function

TODO: std::vector exceptions are not verbose, handle range check myself
Handle range checking myself
TODO file for simplefit.core
Updated tasks, whitespace change
Simpler function pointers for function class

Functions passed to the function constructor no longer needs to be aware
of the class.  It can simply take a vector of doubles.
Global typedefs for convenience