.functions: Make `mkd` `cd` into the last directory in the list

…rather than the first.

Closes #447 and #450.
brew.sh: Install Lua the new way

Closes #453.
.osx: Update `iOS Simulator.app` path

The iOS Simulator app has been moved.

Closes #452.
committing local changes
brew.sh: Update `gnu-sed` option

Closes #454.
adding brew.sh
removing unnecessary files that are replaced by bash_it repo
removing brew.sh