criu(8): massive man page update

This is an attempt to cleanup the man page. I am very sorry this comes
in this one big patch. Here are the changes:

1. Use *BOLD* for literals, 'ITALIC' for arguments (variable
substituions)

2. Do not use <> for arguments, as they are already marked so (italic)

3. Remove details about "criu exec" and remote syscalls execution;
   add note that it's obsoleted by Compel.

4. Some descriptions are shrunk, some made longer, many are rephrased.

5. Formatting: use second-level lists (*value*:::) where appropriate
   (mostly instead of bulleted lists of values).

6. Properly show comma-separated lists of arguments (with second pair
   of [] and ...

7. Proper use of terms 'option' and 'argument' (*--option* 'argument').

8. Other fixes to formatting and English (such as missing a/the articles).

...

98. Change author to be "the CRIU team".

99. Update copyright years, copyright holder is Parallels Holdings.

[v2: rebase]

Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>