add basic ruby contrib layer
bind reposition window to z f
enable semantic mode in python contrib by default
Execute correct `clear` and `man` behavior in (e)shell
Move shell config to spacemacs/init-shell
Lazy loading of semantic for python layer
Update Python readme
Remove the `s` prefix for send to REPL bindings in Python
Update ruby layer readme
Update key bindings for running tests according to the conventions

For ruby and python layers
Remove `s` in send to REPL commands for ESS

according to the new convention
Update conventions for send to REPL and test execution
Fix defvar instead of setq in readme
Add erlang and elixir logo to readme
Add R logo to readme and fix ruby
Missing `:defer t` for `ruby-test-mode ` in ruby layer