By default, if output is a TTY, dotbot will colorize the output. This
patch adds the option to pass `--no-color` to dotbot to have it suppress
this colorization.
Prior to this patch, Dotbot was relying on running with the base
directory being the current working directory. In practice, it was
relying on the install shim to set up this context. It makes more sense
sense to actually execute `chdir()` within Dotbot itself, rather than
relying on the install shim to do so.
Anish Athalye
Jesse Leite
Philip Hallstrom
Casey Rodarmor
Anish Athalye