Assume nil value means a string field
Revert "Assume nil value means a string field"

This reverts commit 10d9582c6073be7491478e53198d84f441f8fb1f.
Mention that string mode ignores whitespace in values
Easily enable verbose logging
Allow '1'/'0'/'' and 1/0/nil in boolean features
Track and report the cardinality of each feature
fix mutex
don't recalc - i hadn't had this correct before
clarify