Cleanup rebar_core and rebar_erlc_compiler

Rename rebar_core functions for improved readability.
Remove redundant comments and blank lines.
Fix default DTL compilation when no erlydtl_opts are provided
Change zsh completion script

- Add 'escriptize' command
- Remove variable 'dump_spec'
rebar_neotoma_compiler: fix comment
rebar.config.sample: document require_*_vsn options
rebar_require_vsn: remove trailing whitespace
rebar.config.sample: document leex and yecc options
rebar_ct: fix wording in comments
Document escriptize command
rebar.config: delete unused and unimplemented 'app_bin' option

app_bin option was used by the install command which has been
removed in 51ed787.
rebar.config.sample: document escriptize options
rebar.config.sample: remove non-existing option
Support environment vars with unicode characters

The results returned by os:getenv() may contain unicode characters.
That said, we need to explicitly allow unicode when splitting the
environment information, otherwise badarg will be raised causing all
rebar commands to fail until the environment variable is removed.
Add missing rebar_qc:clean/2
Merge pull request #27 from norton/norton-qc-clean

Add missing clean/2
Merge pull request #13 from tuncer/fixes

Fixes
Update THANKS
Merge pull request #30 from DeadZen/master

Update THANKS: use my real name
bash-completion: add generate-appups
Makefile: fix 'clean' and add 'distclean'

* fix 'clean' to remove .eunit (not .test)
* add 'distclean' to also remove deps/