fix function defs for function that take vsn(), which can be an atom
include state in format_error/2
use providers PRV_ERROR and format_error/2
Fix *bin_windows.dtl boot script path

In order to make it work with both compressed and uncompressed releases
Merge pull request #250 from syl20bnr/fix_boot_script_console_windows

Fix *bin_windows.dtl boot script path
Merge pull request #236 from tsloughter/format_error2

Some changes for providers as I work on rebar3
include state in format_error/2
support proper return value of ec_git_vsn of {ok, string()}
Merge pull request #251 from tsloughter/master

Bug fix and cleanup