Fixed considering patches that may start / end within a group of nodes to which same pixel-value should be assigned, i.e. patches whose x-dim. is not a multiple of the refinement-factor in x.

Fixing odeint Examples

See merge request openfpm/openfpm_pdata!9

New example and documentation for Odeint in Numerics

See merge request openfpm/openfpm_pdata!8

Fd solver merge

See merge request openfpm/openfpm_pdata!7

Also adding Subset number prop name.