rename Table to Data
move table.py to interactive.py
dplyr uses Symbol rather than TableSymbol
TableSymbol -> symbol in compute
simplify mongo pytest fixtures, lower to values

OK with this sort of change @cpcloud?
remove interactive elements from compute
update docs to Table -> Data switch
Field print itself as t.x rather than t['x']
fix import in api.__init__ for interactive <- table
use t.x instead of t['x'] in docs
Merge pull request #753 from mrocklin/Data-renaming

Some renamings throughout Blaze