logging enhanced

slf4j-logging integrated; JavaDoc & comments added
relativize absolute paths added
unit-tests extended
fields for package-name and -version added
git-ignores extended
m2e-support, commons-libs added
m2e-support, relativize paths

support for eclipse-m2e enhanced
optionally relativize resource-paths to project-root
m2e-support
m2e lifecycle-mapping added
m2e-support, new maven-properties for config
m2e-support
adaption to modified base-classes

support for relativize paths
usage of jdk-serviceloader

usage of jdk-serviceloader for resolving providerfactories (replaceable
factories)
dependencies added
utility-class for relativizing paths
git-attributes added
git-attributes modified
recommit
Merge branch 'pr2'

Conflicts:
	.gitignore
	i18n-maven-plugin/src/main/java/net/jhorstmann/i18n/mojo/AbstractGettextMojo.java
	i18n-maven-plugin/src/main/java/net/jhorstmann/i18n/mojo/GettextMojo.java