changed landing page example from 'gaussian processes' to 'logisic regression'
rebuilt main-built.js
Merge pull request #12 from agfk/time_estimates

Time estimates
added [concept display](concept) shorthand for nodes
fixed url parsing bug in roadmaps and fiddled with css
always rebuild search index when starting server
css fixes and added -contribute- tab to main header
fixed time estimate bug
fixed e-to-l transition bug, changed -learning list- to -learning plan-
updated README and database.py for new naming scheme
Update README.md
updated content_server description
fixed link in about.html
distinguish internal and external links in roadmaps
tweaked roadmap and learn-view css
changed external link color
added css rule to fix all-text-selected problem
improved user account creation: field errors display near fields and duplicate emails are not allowed
allowed optional trailing slash for about and contribute pages
added password reset