Added new methods to get distances and angles between points.
Added new methods to get distances and angles between points.

Added
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* New methods:
  - node_to_node_distance
  - point_to_node_distance
  - point_to_point_angle
  - point_to_node_azimuth
  - point_to_node_vector

Carralex/landlab,decvalts/landlab,SiccarPoint/landlab,laijingtao/landlab,cmshobe/landlab,landlab/landlab,cmshobe/landlab,Carralex/landlab,csherwood-usgs/landlab,SiccarPoint/landlab,RondaStrauch/landlab,amandersillinois/landlab,decvalts/landlab,laijingtao/landlab,cmshobe/landlab,ManuSchmi88/landlab,RondaStrauch/landlab,Carralex/landlab,landlab/landlab,ManuSchmi88/landlab,RondaStrauch/landlab,ManuSchmi88/landlab,amandersillinois/landlab,landlab/landlab,csherwood-usgs/landlab