Basic workflow example in man page

User struggle with understanding the concept of Machinery, when
they don't take the time to read through all the man page. A
quick introduction with examples would help with that.

Since there are already enough descriptions about machinery and
its concept in the man page I just provided examples as a
quickstart guide.
Remove the generated man page part machinery_main.1.md
Update man README about correct path to the main man page file
Merge pull request #321 from SUSE/basic_work_flow_example2

Basic work flow example2
Make hound less strict with line length, disable block check in /spec
Apply ignore list to remote dirs

Make sure that we don't warn the user about remote_dirs in directories
which we are ignoring anyway.
Merge pull request #323 from SUSE/review_141016_make_hound_less_strict

Make hound less strict with regard to block style and line length
Merge pull request #324 from SUSE/apply_ignore_list_to_remote_dirs

Apply ignore list to remote dirs
Mention supported operating system in README
Make specific os detection methods private, introduce "#get_os" instead

"OsInspector#get_os" is the public method that should be called in order
to retrieve the Os object. It cascades the different detection methods
for specific operating systems which makes it easier to use and extend.
Add helper method which ensures that we're running on a compatible host
Abort Machinery when we're running on an incompatible host
System#cat_file -> #read_file, make it os agnostic on local systems

System#read_file used "cat" internally which means that it didn't work on
MacOS and Windows and was also harder to test.
Refactor OsInspector

It now uses System methods instead of implementing its own stuff. That
makes it cleaner and easier to test.