Create of pgr_separateTouching new utility function

[cvvergara]

Create of pgr_separateTouching(edges SQL, tolerance, dryrun) - breaks the edges that touch each other or the dead end is very close to an edge

Example execution (using the Sample Data of the documentation):

SELECT seq, id, sub_id, ST_AsText(geom)
FROM pgr_separateTouching('SELECT id, geom FROM edges');
 seq | id | sub_id |             st_astext              
-----+----+--------+------------------------------------
   1 | 14 |      1 | LINESTRING(2 3,1.999999999999 3.5)
   2 | 14 |      2 | LINESTRING(1.999999999999 3.5,2 4)
(2 rows)