When changing the length of a field, the column name needs to be escaped
properly.

reverted @deeky666 suggestion. Since it failed on testBooleanNullConvertsToPHPValue test. 
with message Failed asserting that true is null.
Since I moved this code from BoolenType::convertToPHPValue in the first place, I presume the code there correct.

updated convert function  to include uppercased values

Description fix

fixed parameter order in conditions

Changes after Ocramius comments

fixed bug when $item was set as bool true value
added 'off' literal

added postgresql literals to Boolean conversion

Default Boolean conversion behaviour