Using (const) access functions in two cases of direct
member access.

This helps to omit const_casts when the point
coordinates needs to be modified.

Clang format run on near-the-header lines.

Happy New Year

This potentially saves a second copy compared to using const
reference. See Effective Modern C++, Item 41.

Only istream is required here.

This avoids another half of the deprecated warnings associated with the implicit
copy assignment in presence of user defined ctor.

Clang reports:
warning: definition of implicit copy constructor for 'TemplatePoint<double, 3>'
is deprecated because it has a user-declared destructor [-Wdeprecated]

Update documentation.

Extend the input to arbitrary TemplatePoint,
but it is working only for TemplatePoint<double, 3>
== Point3d for now.

The lexicographic comparison is now working for
arbitrary TemplatePoint dimensions and underlying
floating types.

... into TemplatePoint header file.

Using the removed constructor was insecure because there was neither a
compile time check nor a run time check if the size of the C array holds
enough data.