Improving documentation

[grhawk]

Let's try to gather in this post all the problem regarding the documentation: inconsistency, points that need clarifications... and so on.

• Units of input files(Units again, this time in the LAMMPS interface #164): the only documentation regarding the string used as the values for and must be divined from the first tutorial in the manual. Should be MUCH more systematic: each possible string should be contained in a table with all the associated default behavior plus a general comment on how to set units of the input files.

• Document the default behavior of the replay mode if no "CELL" is specified in the trajectory file that it is reading (can be a problem for manually made trajectory files in periodic cases, if users don't know). Any other default behaviors of the replay mode that should be better documented? (MR)