- add overlay_vars=, target_dir=, and tests= with short description

- add missing short and long options
- add tests=, target_dir=, overlay_vars=

- Add 'escriptize' command
- Remove variable 'dump_spec'

For enable to shell-completion in zsh.

This allows the node to run in paths which include special characters,
for example 'C:\Program Files (x86)\Product Name'

This patch contains two additions to simplenode.runner:

1. Check if vm.args exists in CWD; if so, use it. This makes it
   easier to start multiple concurrent nodes on a single machine
   from one rebar-created release (starting each node from its
   own directory, with its own copy of vm.args and e.g.
   sys.config, log directory, database directory, etc.)

2. Add the targets start_boot <file> and console_boot <file>.
   This is used to select a different boot script. The 'setup'
   application (http://github.com/esl/setup) builds a special boot
   script for installation (all apps loaded but not started,
   making it possible to run install hooks with the full code path
   in place).

* Typos and other minor bug fixes
* Add "attach" command (via -remsh)
* Add "upgrade" command to install a hot upgrade package
* Add "upgrade" subcommand to UNIX runner script as well

bin/<release_name> console -kernel test '[{"a","b"}]' fails, because
when $@ is inserted into CMD [{"a","b"}] is interpreted.
Fix the same issue for 'start' command and quote all arguments.

This change adds the ability to use alternate urls for downloading
dependencies. To make use of alternate urls run:
rebar get-deps alt_urls=true

Args provided by erlsrv.exe were being mostly
discarded due to being processed through set_trim

app.config has been a long standing erroneous file in rebar. Erlang/OTP
documentation suggests a sys.config file instead. This file is stored in
the releases/VSN directory. This does a few things but most importantly
it ensures your config (contained in the application environment)
survives a hot upgrade. It also has the advantage of allowing the
configuration of the application to be versioned along side the
application code. This patch flips rebar to use sys.config rather than
app.config.

Additionally it makes this flip to vm.args as well, making them
versioned just like sys.config.

This patch also includes runner script changes to support the old
etc/app.config config file location and support for Windows.

Thanks to mokele for the initial work and kick in the pants to make this
finially happen.