Merge pull request #5371 from RosettaCommons/roccomoretti/speed_up_conformation_hh
Attempt to speed up compilation of Conformation.hh
The compilation of Conformation.hh is rather slow, so I poked around a bit to figure out how to potentially speed it up.
* Remove the ParametersSet header from Conformation.hh
* Don't include utility/string_util.hh in xyzVector.hh (use std::to_string() instead. -- also clean up string_util.hh use in headers generally)
* Remove numeric/trig.functions.hh from xyzVector.hh (move related functions to utility file.)
* Push the hash function for xyzVector to the one place it's used, which allows us to remove the (heavyweight) boost/functional/hash.hpp header.
* Reduce need for various io-related headers from xyzVector.hh