Added more 'constness' to the mematrix class.

- Converted the one version of the overloaded subscript operator [] to two versions: one for read access (const) and one for write access (non-const). This allows more consts in other functions declarations.
- Removed some commented code and minor changes to the code layout


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/genabel@1713 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Added consts to the base_reg, linear_reg and logistic_reg classes.

Also includes a little bit of code layout improvements.

The biggest questions that remain are: why is there and assignment nullmodel = 0 in the calls to the score() functions of linear_reg and logistic_reg? Is this a simple copy/paste error?


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/genabel@1714 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Fixed a few cppcheck warnings by initialising some variables in initialisation lists.


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/genabel@1715 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Fixing some cpplint warnings in ProbABEL's reg1.{cpp,h}.
Added some more consts in these two files.


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/genabel@1716 edb9625f-4e0d-4859-8d74-9fd3b1da38cb