Nitgs semiglobal

The series add some optimizations on nitg-s and nitg-e engines

Some numbers with nitg

~~~
$ nitg nitg.nit
$ time nitg nitg.nit
user	0m12.424s

$ nitg --erasure --inline-coloring-numbers nitg.nit
$ time nitg nitg.nit
user	0m11.672s

$ nitg --erasure --rta --semi-global nitg.nit
$ time nitg nitg.nit
user	0m10.004s
~~~