More changes to correctly react to book_electronic, journal_electronic and electronic

bibsearch.js
-Changed exact match "electronic" to indexOf "electronic" so that the
"how to access"/"where is it "-button reacts correctly to
book_electronic and journal_electronic

bibsearch_init.js
-Changed bookformat-handlebar to react to book_electronic and
journal_electronic
-Added Handlebar-helper ifContains, unlessContains and ifItemType

index.html
Replaced ifCond and unlessCond with ifContains and unlessContains to
check for all types of electronic material