comparator can be a key string; watch it if it is
manage comparator and watched apart from filters

and prevent filter reset from wiping their watches
ensure configure with clear clears the whole config
ensure that configure applies whole new config
test configure, spec, and watched changes
rename _reset to reset; truly reset
monitor changes to comparator key more simply
make _unwatch work like _watch
cache filtered models before slicing; ref #6
updated tests for changes
_parseFilters --> _parseSpec and init things there
make sure 'reset' fires events.
use '_resetFilters' in 'configure' instead of 'reset'.
add tests for 'reset'
add tests for 'clearFilters'
removing 'comparator' should set it back to parent's 'comparator'
includes #27
move comparator reset to _resetFilters

- put it behind a param flag
- corrects bug with configure({}, true) not resetting comparator
docs update
Added note about manual watches; ref #3
Adding a few more code ticks to readme
removing '_spec' since it's no longer used
add missing arg to _.contains
comparator resets to undefined
2.0.0