Adding snippet for defimpl.
Correcting ST2 instructions to match typical package directory naming conventions.
Adding basic ignore.
Specifically, ignoring editor-generated caches of sippets, etc.
Merge pull request #21 from ybakos/defimpl_snippet

Adding snippet for defimpl
Merge pull request #22 from ybakos/ignore_and_readme

Minor changes to ease bundle development via ST2 (ignore, README fix)