allow p:library imports and fix non-existing directories

fixes #5
fixes #13
Merge pull request #14 from daisy-consortium/fix-library-import-and-nonexistent-directories

allow p:library imports and fix non-existing directories
Merge branch 'master' into xproc-maven-plugin

Conflicts:
	www/documentation/test-results.html.html
	www/documentation/test-results.junit.xml
	www/documentation/test-results.result.xml