Use INTEGER for all integral types on SQLite.

From http://www.sqlite.org/datatype3.html it seems that SQLite does not
distinguish at all between the different types, so in general it does
not matter which one you use (and all the standard names are understood
by SQLite), except for Auto-Increment columns where you must specify
INTEGER as the type.
Merge pull request #909 from slick/tmp/sqlite-integer

Use INTEGER for all integral types on SQLite.