Methods that enable to calculate the EDCPTD centrality for a project are
added to a provisional file 'util-tensor.R'. This include methods that
retrive the needed single-layer developer networks, a method that builds
a forth-order tensor using this single-layer networks and e method that
calculates the EDCPTD centrality using this tensor.

Signed-off-by: Anselm Fehnker <[email protected]>

The process of how EDCPTD centrality is computed is changed. In the
first step the author network for each relation is build. In the second
step the author networks are converted to a forth-order tensor and in
the third step EDCPTD centrality is computed.

Changes are based on the reviews from @clhunsen, @bockthom and
@ecklbarb.

Signed-off-by: Signed-off-by: Anselm Fehnker <[email protected]>

The use of the library rTensor is added to the 'README.md' file.

Signed-off-by: Anselm Fehnker <[email protected]>

Apply the Review from @bockthom and @clhunsen on the previous changes.
This includes compliance of coding conventions, update of copyright
headers and improvement of documentation. Move the functions for
'get.author.names.from.networks' and 'get.expanded.adjacency' to new
file 'util-networks-misc.R'. Also add two functions
'get.author.names.from.data' and
'convert.adjacency.matrix.list.to.array' from the 'dev-network-growth'
project to the new file.

Signed-off-by: Anselm Fehnker <[email protected]>

The changelog file 'News.md' is adjusted. The section '## Unversioned'
is added above the latest release version. The new features added in
this Pull-Request are described in the subscetions '### Added' and '###
Changed/Improved'.

Signed-off-by: Signed-off-by: Anselm Fehnker <[email protected]>