* \li Syntax: vc-compare <REV1> [<REV2>]
* \li Params: Revision number either points directly to commit in history
or if negative number -x it points to last commit - x.\n
- In RCS we subtract only in the last part of revision specification.
+ In RCS we subtract only in the last number of revision specification.
Special case "0" is reserved for the last committed revision.\n
<REV1>: Older file.\n
<REV2>: Newer file. Used only if REV1 > 0.