Although yet untested (but it compiles and is still unused) add UAT to the repo.

Although yet untested (but it compiles and is still unused) add UAT to the repo.
UAT is an API to handle User Accessible Tables,
an UAT is basically an array of arbitrary structs that has a file representation
as a mean for mantaining things like:
- the snmp_users_table
- dfilter macros
- ipsec/ssl key bindings
- k12 configuration,
- and many other table-like user modifiable preferences

comming soon gtk's uat_window() and prefs_add_uat()

uat.h is fairly doc[uo]m[m]?ented, a README with a simple example of how is to be used will be available as I write them

svn path=/trunk/; revision=20586