improved documentation: ${basedir} for profile activation is Maven 3
only
MNG-5608: warn if file-based profile activation uses ${project.basedir} since only ${basedir} is supported
make warning for ${project.basedir} and ${project.*} different: first
should be replaced with ${basedir}, latter is simply not supported
[MNG-5610] README.txt in distro should be updated

Signed-off-by: Anders Hammar <andham@apache.org>
[MNG-5612] avoid fully interpolated values for file based profile
activation values but effective values calculated during activation
disable interpolation on full profile activation, not only file based