Added a reprocess option.
Reverted the tip about watching asset files.
Warn instead of die when reprocess is used in production mode.
Documentation for reprocess option in description for register.
Merge pull request #1 from alexander-rymasheusky/feature/4/reprocess

Feature/4/reprocess
Changed reprocess option to environment variable; renamed to PROCESS_ON_EXPAND.
Renamed the reprocess option to NO_CACHE.
Read environment variable only once, on plugin registration, instead of each time in usage.
Renamed the test file that tests no_cache option to match the option name.
Merge pull request #2 from alexander-rymasheusky/feature/4/reprocess

Feature/4/reprocess
Merge pull request #9 from alexander-rymasheusky/master

No cache option (issue #8)