Merge pull request #1 from modxcms/develop

Update
Clean code. db->query() cannot return false
Convert loops from "for" to "while"
Bugfix
Update db->delete()
- add message when $from is empty
- param check
Single style delete from db -> use db->delete()
Use db->getColumn() instead of loops
Use db->makeArray() instead of loops
Use db->makeArray() instead of loops
Convert loops from "for" to "while"
Clean code. db->query() cannot return false
Use db->truncate()
Merge pull request #182 from Segr/develop

Query, Delete and other optimization