add rels.py: extract mention and retweet relations between users
build nodes and links based on mentions, with counts
produce json output like http://bl.ocks.org/mbostock/4062045
produce json output like http://bl.ocks.org/mbostock/4062045
Merge branch 'rels' of https://github.com/pbinkley/twarc into rels
rels.py output works with D3 example
proper output for rels.py
added directed graph version
refactored rels.py and directed.py to generate self-sufficient html
handle -m parameter to choose mentions or retweets
removed rels.py and rels.html - they were drafts of directed.py
changed -m to --mode for consistency with other utils
updated README.md and .gitignore for addition of utils/directed.py
added tooltips with user name and out/in counts
basic highlighting of in and out links on mouseover
highlight clicked node with paths and branch nodes
colour distinction for in and out links and nodes in css
colour distinction for branch nodes that have both in and out
refactored highlight classnames to use same names on all element types
added working dirs to .gitignore