[#897]: Interpret subpackages and classify classes into them
#639: Add HTML Purifier to Composer

This commit prepares the solution of #639; where we are going to add an optional guard against
XSS attacks. The guard is optional because it slows down running phpDocumentor ten-fold and
90% of the projects have trusted developers.

For people doubting about trust or running public uncontrolled services can they enable this
safeguard.
Merge branch 'develop' into release-2.0

Conflicts:
	composer.lock
Merge branch 'develop' into release-2.0
Removed references to the manual installer
Made a fix for windows users; files should now be written to the correct location
Add support for generating routes for file templates
Minor DocBlock fixes
Fix inheritance for Interfaces
Only generate a key when a default value is actually provided
Add text to @deprecated example for more accurate testing
Expanded changelog with latest fixes
Rewritten several old-style validators to new ones
Update reference implementation file with more examples
#919: Register custom title with XML output
[#918]: Fix missing packages when using XSL templates
Remove generate template and package command
Add clean template and set as default
Remove redundant syntax highlighter
Removed reference to template generator