update dockerfile -- add python-sympy 

This adds the sympy CAS package to supplement the other packages python numeric packages, such as numpy.
Merge pull request #29 from jverzani/patch-1

update dockerfile -- add python-sympy
Show notebook header.Update dockerfile,nginx,setup

- Showing notebook headers. Headers hidden only in the start screen.
- Updated nginx version.
- Updated Dockerfile to use official ubuntu image instead of that from saltstack. Added vim.
- Fixed typo in setup script for sysinstall_resty function.
Merge pull request #30 from tanmaykm/tanmaykm

Show notebook header.Update dockerfile,nginx,setup