Some fix on the pwn_g2o files.
Fixed bug on the pwn_mapper_controller
pwn_mapper_controller pinholepointprojector substituted with multipointprojector.
pwn_mapper_controller now use a 4 pinholeprojector multiprojector.
Merge branch 'master' of https://github.com/grisetti/g2o_frontend

Conflicts:
	g2o_frontend/pwn2/multipointprojector.cpp
	g2o_frontend/pwn2/multipointprojector.h