basic obspy tutorial

Examples to read and write SEG-Y files from `obspy ` packages. One
method is still missing, the ability to create a `SEGYFile` from an
existing file that contains a valid header.
Add .gitignore

add `.gitignore` to remove `.ipynb_checkpoints` and cleaned up some data
files that are now present at the `data` folder.
Fix #2 .gitignore

now should be ok!
Merge pull request #3 from oliveirarodolfo/ObsPy

#1 merge to ObsPy branch