A lot of clean up. Mostly CLI-related. Moved from org.clojure.tools.cli to clojopts (clojopts is getops-compliant). Better CLI. Better debugging output. Details below:

1. Switched to clojopts. Help is printed nicely now. Combining options, i.e. drake -aw file.d is now possible, in line with getopts standard.
2. Rearranged options for readability in --help. Lots of small editing there.
3. Debugging mode is now turned on only by --debug. -d is reserved for future use.
4. --trace is added for more verbose debugging information (--debug now prints much less than before).
5. Added a new option: --step-delay to specify the amount of time, in milliseconds, to wait after each step. Should help with desynchronized filesystems (https://github.com/Factual/drake/issues/15).
6. Time consumed by a step is now printed as "-- done in 0.15s + waited 50ms"
7. Fixed resources/regtest/regtest_fs.d to use local filesystem (/tmp) in case HDFS is not available. All regression tests pass now. Aaron, please test it on HDFS as well.
8. Added checking for conflicting options (https://github.com/Factual/drake/issues/25).
9. Had to delete stopts!?, since --help is handled directly by clojops, so we don't need it any more. Sorry, Aaron.
10. Some small refectories here and there.
11. As usual, some cosmetic fixes.
1. ':' are now allowed in filenames (drake switches to local filesystem instead of issuing "invalid filesystem prefix" error)
2. better error reporting, less stacktraces
Fix for https://github.com/Factual/drake/issues/34

1. Switched from absolute output filenames for generating temporary directory names to relative, because they're shorter.
2. Implemented maximum directory length restriction.
3. Temporary directory uniqueness is now ensured before steps are run, on the parse tree level. Disambiguated with .0, .1, … indexes.
4. Better logging.
5. Some cosmetic changes.
Merge branch 'feature/vvv' into develop
Merge branch 'feature/filenames' into develop