new function to create random string
addig some doc about postgis topology
adding a split of lies by  points with tolerance
it works wihtout tolerance issues
workink alpha version of split lines by points
have been tested, but not toroughly used.
fix : now split lines by point is SRID safe !
it was due to the fact that dumppoints put all srid to 0
Cleaned the select to avoid noise
Merge branch 'master' of https://github.com/Remi-C/PPPP_utilities