[ADOL-C] warnings using g++ -Wconversion

[Brad Bell]

I notice some warning when I compile adol-c code with
	g++ -Wconversion
For example:

/home/bradbell/prefix/adolc/include/adolc/advector.h:130:132:

warning: conversion to ‘locint {aka unsigned int}’ from ‘size_t {aka 
long unsigned int}’ may alter its value [-Wconversion]

ADOLC_DLL_EXPORT advector(const advector& x) : blk(x.size()), 
data(x.size()) {  adolc_vec_copy(data.data(),x.data.data(),x.size()); }