make the autoproj message-to-user API match the one in autobuild
make the Ruby package class parallel-compliant
define the --version option
modularize the osdep support and create a test suite

This will allow a more flexible osdep structure, and more easily
plug new package managers in the system.
fix minor issues when a package name is a substring of another

Let's say we have two packages

  asguard/orogen/asguard
  asguard/orogen/asguard_deployment

Before this patch, they would get selected for each other even if
they should not. I.e. doing amake in one of the two directories
would automatically select also the other one.
fix URL
Config:: is deprecated, replace by RbConfig::
YAML syntax fix for psych

It seems that psych (the default YAML parser in ruby 1.9.3) does
not like [\w\d\.\d, ..]. Quote these.
properly catch YAML parsing errors from Psych
fix dependencies, autoproj requires newer versions of autobuild and utilrb
make auto-addition of packages smarter by looking into the topmost directories that match a given criteria

This fixes #101
osdeps: integrate back pacman and emerge package managers
bin: add -p to set the parallel build level on the command line
push 1.8.0.rc1
update changelog
fix the --show and --revshow options of autoproj osdeps
dist: fix hoe declaration
osdep: reset @operating_system to nil if :force is set

Otherwise, the followup logic assumes that we already have an OS
detected and won't update it.
properly handle YAML load errors on Ruby 1.9

The exception class changed, so selectively pick the right class
define #version on PackageManifest