Fix #30: Thrown exceptions leave connections in an undefined state.
Avoid using deprecated vibe.d symbols.
add colNames and colNameIndicies to ResultSequence

- same as in ResultSet
detect nullable types and call nullify in toStruct
Merge pull request #36 from MartinNowak/columnNames

add colNames and colNameIndicies to ResultSequence
Merge pull request #37 from MartinNowak/nullify

detect nullable types and call nullify in toStruct
fix empty for ResultSequence

- Range wouldn't stop correctly when all rows were fetched
Merge pull request #38 from MartinNowak/SequenceEmpty

fix empty for ResultSequence
Merge pull request #1 from rejectedsoftware/master

merging master changes