Update README

Simple description and "how to".
Added header attribute which stores only page numbers in simple (X)
and complex ("customtext" X из TOTAL) format.
Merge remote-tracking branch 'origin/master'
Added header attribute which stores only page numbers in simple (X)
and complex ("customtext" X из TOTAL) format.
Added header attribute which stores only page numbers in simple (X)
and complex ("customtext" X из TOTAL) format.
Added PropertyGetterTest for plain json strings.
Merge remote-tracking branch 'origin/master'

Conflicts:
	README
	src/main/java/ru/onyx/clipper/events/HeaderEvent.java
	src/main/java/ru/onyx/clipper/model/Report.java
	src/test/java/ru/onyx/clipper/TestReport.java