Update to Sisu 0.1.0

Sisu depends on Guice, but dependency scope changed from "compile" to
"provided" in Sisu 0.1.0.  As a Sisu user, XMvn needs to have runtime
dependency on Guice.
Avoid NPE in FileUtils.followSymlink()

artifactFile can be null only in case artifact was attempted to be
resolved from bisection repository, but resolution failed.
Add limited support for absolute JPP artifact files

Artifact files specified as absolute paths pointing to arbitrary
locations are now allowed.  They are implemented as symbolic links
which are pointing to the primary artifact file, which must be
explicitly specified as non-absolute file.

Appropriate suffixes are added depending on artifact version,
classifier and extension.  As absolute symlinks can be placed at any
location, configured repositories are not taken into account and flat
repository layout is always assumed.

Absolute symlinks are only created for artifact files and attached
artifacts, but not for POM files.  Absolute files for artifacts with
no files (i.e. POM artifacts) are silently ignored.
Fix a typo in error message
Fix extension and classifier suffixes in absolute files
Allow file installation in root directory

Root directory path does not have a parent, so it needs to be treated
with care not to trigger NPE.