support config of multiple rails via ENV or TOML

factors configuration reading into separate file within same package

uses TOML array syntax to capture rails

environment variable names are noted with zero-based array index (i.e.
GL_RAIL_0_NAME, GL_RAIL_1_NAME, etc.)

updated README to include usage
Merge pull request #5 from abargnesi/configuration_options

support config of multiple rails via ENV or TOML
fix up title
check error return from first getenv
reformat config.go for some reason
reformat main.go (?)

I'm not, some part of vim-go is.
swap out port-based confg for @abargnesi rails
add debug script, cgdb ftw :beetle:
break reading env if at least one rail is present
fix release script
provide a release name
don't crash if no env vars or cfg is present