Local windows support:
- Add dos2unix task for config
- Run dos2unix on code only if it was deployed via remote copy
- Introduce FIX_LINE_ENDINGS env var to force dos2unix to run
- Refactor rubber:config task to have sub tasks :push and :configure, so we can hook dos2unix between the two steps.
- Remove use_dos2unix variable (which was introduced in early attempts at Windows support)