r2llib interface change requests

[guy keren]

i'm integrating the base directionality support into the plugins code, and
found some inconsistencies and inefficiencies:

1. BT_ERROR should be renamed 'BT_BASE_ERROR' to be compatible with the
   other constants of its enumeration.

2. there should be a single function that gets both r2l mode and biditext
   base directionality - using a single stat() call. having to call 2
   seperate functions is inefficient - especially inside biditext's string
   drawing code...

--
guy

"For world domination - press 1,
 or dial 0, and please hold, for the creator." -- nob o. dy