Fixed errors in Readme.md
Added arguments checking to _markdown.py
Added some russian/USSR books
Added one more russian book
Added note for Vaganova book
Added rule to 'make entrycount'
Added dependency from bookmark package
Fixed error in russian.bib
Added option to ignore default bibliography sources
Removed default list-style from _reset.css
Added 10 musical-dance instructions from LOC
Added 10 more musical-dance instructions from LOC
Added 10 more instructions
Removed Vaganova full-fledged digital (I don't have it)
Added 8 more dance instructions from LOC
Finished working with neweset LOC sources
Implemented automatic write of biblatex-dm.cfg file
Fixed ids in american.bib
Fixed date of some russian books, added one more russian books to problems.bib
Moved 'Lucy Neal Quadrille' to problemmed books