Update all license headers
Add RETRY <n> clause to COPY.
merge MMcM: Add RETRY <n> clause to COPY.

Merge pull request #51 from MMcM/sql-parser/copy-statement-retry
https://github.com/FoundationDB/sql-parser/pull/51
merge nathanlws: Update all license headers

Merge pull request #50 from nathanlws/sql-parser/fdb-license-update
https://github.com/FoundationDB/sql-parser/pull/50