various CSS changes and fixes
add a context menu when selecting text in concordance and KWIC views: note the ranked relevance link doesn't work yet
fix ranked relevance with context menu, fix context menu when selecting a work on the far right
fix bug #20 "Concordance Report, Truncated entries"
fix issue #10 "Collocation span" where filtered words were not counted as collocates
Merge pull request #32 from clovis/master

Various fixes