* Stuff
** DONE group_by default function
** DONE group_by_count
** DONE group_by_array
** DONE Remove special subs
**** DONE docs
** DONE Fix throw, remove lib
** DONE Release
** DONE Deprecate Array::Transform, point to new
** DONE map_by, grep_by, group_by hash key lookup
*** if first item is ref HASH
** grep_by - value
** [#A] group (group_count)
*** group_array
** sort
** find(sub), like grep
** find_by($method, $args, $value), like grep_by but first
** contains value
** compact - without undefined
** compactTrue - without false
** without - grep -v value
* Hash
** DONE key_value($key, $new_key_name=$key) : ($new_key_name => $value) | { $new_key_name => $value }
*** exists
*** exists, undef
*** doesn't exist, undef
** DONE key_value_if_exists($key, $new_key_name=$key) : ($new_key_name => $value) | { $new_key_name => $value }
** DONE key_value_if_true($key, $new_key_name=$key) : ($new_key_name => $value) | { $new_key_name => $value }
** DONE key_value_if_defined($key, $new_key_name=$key) : ($new_key_name => $value) | { $new_key_name => $value }
** keys_value* to support multiple pairs
*** if there are more than one arg, assume they are pairs
** map family
*** map hash -> array
**** [#A] map_each_to_array($subref)
***** ($key, $value), $_ is value
****** return value (or die) to be list item
***** return array with return values
*** map hash -> hash
**** [#A] map_each($subref)
***** ($key, $value), $_ is value
****** return new key, new value (or die)
***** return hash with return values
**** [#C] map_each_value($subref, $new_key = $key)
***** ($key, $value), $_ is value
****** return new value
***** return hash with same key, return value
**** map_each_value_by($accessor, $new_key = $accessor) maps values from one thing to another
***** (key, $value, $accessor_value), $_ is accessor_value
****** return new value
***** return hash with same keys + $new_key = return value
**** map_by ?
** grep family
*** grep -> hash
**** [#A] grep_each($subref = true)
***** ($key, $value), $_ is value
**** [#B] grep_each_defined
***** value is defined
**** grep_each_by($accessor, $args?, $subref = true)
***** ($key, $value, $accessor_value), $_ is accessor value
**** grep_each_by_defined
***** accessor value is defined
