Add some recommended settings in README

Use of `paredit` or `smartparens` minor modes is added as a possible
recommendation for lisp modes. Also a small snippet added to add this
to hook. Tries to address the issue raised in #20
Merge pull request #21 from theanalyst/enhance/readme

Add some recommended settings in README
make indent-tabs-mode nil

This commit sets indent-tabs-mode to nil by default in hy-mode so that
tab doesn't get introduced
Merge pull request #22 from theanalyst/f/tabs-vs-spaces

make indent-tabs-mode nil