change data directly in mysql for some tables

search-replace on tables that don’t contain serialised data can be
changed directly in mysql
Handle shorter versions of item keys
Handle non-numerically indexed arrays too
Tests for #803
Accommodate both types of items
Accommodate array iterators, which can be passed to `display_items()`
Only modify relevant output formats
Merge pull request #803 from wp-cli/fix-803

`--fields=title,content` should work
Update to php-cli-tools latest, which fixes Hungarian cron list
check for serialized before running serial safe replace
Single quote table and col names for edge cases
now quotes on table name
Spell count correctly
Formatting and variable names
Add backticks and show which replace is used
Back tick all the things and better debuggin
Use checksum API to verify core files
Core only offers checksums down to 3.7, so this will have to do

Let's always test against latest though
Safe flag and table output
Merge pull request #1219 from wp-cli/fix-1219

Hungarian cron list