Remove the .py extension from the script name
Add distutils setup script

Distutils automates the task of installing sdssDR9findingChart into
/usr/bin (or equivalent directory), adding it to the PATH environment
variable so that it can be directly started from the command line.
Update installation instructions — it's now done with distutils
Merge pull request #5 from vterron/issue2

Add distutils installation script. Closes #2