blaze server uses name appropriately

http://flask.pocoo.org/docs/api/
test on travis
update README
travis: install toolz from pip, not conda

it's updated more frequently on PyPI
server: reverse name and datasets kwarg order

Allows

    Server({'name': data})

Rather than

    Server(datasets={'name': data})
add server docs
tiny edits to docs
into: (DataFrame, TableExpr), uses columns
revamp quickstart
minor edits to quickstart
add comments and simplify quickstart language
remove bitcoin example, switch to iris
add iris datasets
move iris datasets to data directory
link to iris dataset
remove data web language from readme

This sounds too sales pitch-y
coerce is multiply dispatched
spark coerce
Merge pull request #363 from mrocklin/server-docs

Docs - Server and quickstart
spark test robust to spark absense