TODO

                                                       -*- outline -*-

* CCS2

** implement the extact R6 algorithm

** autodetect the logic symmetry of molecule
and a general method to deal with symmetry relation functions.

** use a faster algorithm of CCS2
ref: JCC, 18(2), 277-289, 1997

** count hit times of each conformations.

* Molecule
** clean Molecule class
keep Molecule class small and clean, remove other methods to
src/Molecule/tools.py.

** support more file formats
PDF
gjf
mae
Tinker int

** support auto-detection of file format

* Tinker
** detect error happened
If the input parameter is error, for example, xyz file not exist or
param file not exist, the program will hang.

* test
** add confsearch testsuite for cyclopeptide