Experiment to draw PCA plot of strains

- WIP.  but seems to work
Add strain mouse-over support
Highlight row on mouseover
Add timing log info
Merge branch 'master' into mds

Conflicts:
	pan.coffee
	pan.css
Click on the MDS reorders too
Fix bug rendering
Experimental PCA instead of MDS

- Neither quite right :/
Click anywhere in the row to put it first
Merge branch 'master' into mds
Run the (slow) PCA only when idle
Draw order of strains according to first dimension of PCA
Fix bug in mds range selection
Merge branch 'master' into mds

Conflicts:
	pan.coffee
	pan.html
Put MDS above pan plot
Merge branch 'master' into mds

Conflicts:
	pan.coffee
Fix bad indenting
Add a "thinking" display when pca is slow
Mouseover on text labels
Switch to SVD rather than CMDSCALE

- Much faster.  Need to check it is actually accurate!