(doc) Simplify Windows build instructions

Use CMAKE_PREFIX_PATH instead of having separate variables for each
project, and install all projects to the same location.
Merge pull request #227 from MikaelSmith/doc/master/simplify-Windows-instructions

(doc) Simplify Windows build instructions
(CFACT-145) Implement Facter.debugging and Facter.on_message.

Implementing Facter.debugging and Facter.on_message in the Ruby API.
This enables logged messages to be intercepted by clients like Puppet.

Adding the "none" log level that disables log output.

Adding --color and --no-color options to control cfacter's log coloring.

This commit also silences the noisy output (and often confusing) log
output during unit testing.
Merge pull request #229 from peterhuene/cfact/145

(CFACT-145) Implement Ruby API looking hooks for client applications like Puppet.

* peterhuene-cfact/145
  (CFACT-145) Implement Facter.debugging and Facter.on_message.
  (CFACT-145) Implement trace command line option.
  (CFACT-145) Replace trace command line option with log-level.
  (maint) Fix unescaped '\' character in doc comment.
(CFACT-145) Fix segfault when libruby is not found.

When setting up whether or not stack traces should be printed with
exception messages, we set the option on the ruby object outside of
where it is being checked for null.

The fix is simply to move the line up inside the block where ruby is
valid.