fixed compiler warning in VtkWriter

loop indices are now of type 'unsigned int', as they are compared with other unsined ints
migration to the f-wave solver
created class SWE_DimensionalSplitting

new option in the scons configuration to use the DimensionalSplitting implementation of SWE_Block
Merge branch 'master' of https://github.com/farad91/SWE

Conflicts:
	submodules/f-wave-solver