Merge pull request #4335 from RosettaCommons/vmullig/int_to_size_in_string_util
Fixing bug that was preventing read of some large text files.
In our string utilities, we have a function that reads in a text file and returns a string with the file's contents. This function reserves space based on the number of characters read in. This count was unfortunately being stored in a standard, signed int, which meant that long text files could result in overflow and a negative value being passed to string::reserve(). This corrects this by switching the integer to a platform::Size, which guarantees that the number of numbers that can be stored is greater than or equal to the maximum size of string that you could store.