Assorted improvements to summary Rnw doc

[ahfoss]

• [x] - Use scientific notation for variable means in table 1, and other tables where appropriate (e.g. maybe Table 2)
• [x] - Report min, maxs in table 1
• [x] - Include size of file analyzed in GB
• [x] - Include number of lines in the data set (probably from previous calculation)
• [x] - show weighting of variables on pcs 1 and 2
• [x] - Log scale for L1 distance plot, in addition to standard scale plot
• [x] - legend matching cluster number to color in PC plot