Update install script

- When initial setup is run, user is prompted for flags to pass to
  install script in order to customize installation; however, since bash
  doesn't pass along variables to subroutines, need to pass along entire
  flags and check again for valid flags
- Update install script to pass along flags to brew library script
- Update brew library script to check for valid flags that are passed
  along
- Update `mirrorfiles` script to hardcode ${BASH_DIR} as ${HOME}/.bash
  in case the script chokes on invalid variable scoping
- Delete flag passed along to `mirrorfiles` script as its no longer
  necessary
- @TODO: must be a better way to do this, maybe export settings or
  figuring out how to pass variables to subroutines

Issue: #37
Delete computer naming from osxdefaults script

- This needs to be changed to a prompt from the user to set the computer
  name as currently its causing conflicts on the network since the test
  computer and mine are fighting for the rights to the "macbook-air"
  name.
- Doesn't work currently anyway as its checking a flag that isn't passed
  along since bash doesn't pass along variables to subroutines.

Issue: #37