while reading dosages in mldose file the results were saved as strings. These were resized and converted to a pointer. I repaced this sting for a fixed size char array which results in a 20% faster loading time for a mldose file.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/genabel@1662 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
mldose_strtod returns Na if the first character is a 'N' -> should fix examples

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/genabel@1663 edb9625f-4e0d-4859-8d74-9fd3b1da38cb