When creating a table, all the primary key columns are assumed to be
not-null. Adjust them if incorrect.
Add test for multi-part PKs also work correctly
Add tests to support ALTER TABLE ADD PRIMARY KEY() to also perform the
implicit change to the columns of the index to all be NOT NULL.
Merge branch 'master' into pk-columns-adjusted-not-null

Conflicts:
	src/main/java/com/foundationdb/sql/aisddl/AlterTableDDL.java
	src/test/java/com/foundationdb/sql/aisddl/AlterTableDDLTest.java
merge tjoneslo: When creating a table, all the primary key columns are assumed to be not-null

Merge pull request #1342 from tjoneslo/sql-layer/pk-columns-adjusted-not-null
https://github.com/FoundationDB/sql-layer/pull/1342