Add more xliff2PO functional tests for bug 2879

enhanced to catch command argument/option parse errs
Use more idiomatic PATH concatenation

revisiting code I added for bug 2814, now with better Python skillz
http://bugs.locamotion.org/show_bug.cgi?id=2814
Don’t use the old py.test module name

Module name has been renamed to pytest for a while now, use the new name
consistently.
Replace hyphen with space when escaping queries

Otherwise words containing hyphens are not found.

Before: “add on” finds “add-on” but, “add-on” does not
After: both return result
Add test for querying whole strings
Move release notes and instructions to docs/

This follows the same format as Pootle.
Move API to the end of the documentation
Forgot this file
Try higher heading for the title
Add 1.9.0 and 1.8.1 release notes
Forgot to include 1.9.0
Nicer simple human release dates
Add section of GitHub hook, Bugzilla and commits

Commits formulated in the correct way allows comments to bugzilla bugs
and allows closing of bugs.

Fix bug 2895
Fix list
Reword bugzilla githb hook section

Turn it into a list for easier reading
Docs: Typo