[GRASS5] Parameter names inconsistency - vector modules

[Markus Neteler]

Hi,

some vector modules show inconsistencies with parameter names.
As most of these parameters have been introduced recently (or
in a beta in 5.0)  I propose to correct that. Later, in 5.1
we will completely cleanup the parameter structure.

Here I am only thinking to clean "category number" and "category label"
which regularly leads to confusion when not named properly.
Examples:

d.area help
[...]
   category   List of area categories to display

 -> should be 
   catnum     List of area category numbers to display


-----------------------------------------------
v.in.shape help
[...]
  attribute   Name of attribute to use as category

 -> should be 
   catnum     Name of attribute to use as category number

-----------------------------------------------
d.vect.cats help
[...]
   cat   Vector category type to be displayed

 -> should be 
   catnum     List of category numbers to display

Suggestion: The latter shall go into d.vect anyway (to be compliant with
d.rast and to reduce the number of modules).

If there are no objections, I will change above.
Like that it's too confusing in my opinion. Suggestions are
welcome of course!

Markus