using sqlite prepared statement api more effectively.
minor performance tweaks.
added field types table to output db for rebuilding non-fundamental db types. fixed bugs.
query now returns properly reconstructed blob and uuid types
refactored binding into single method
fixed error msg. added back some sqlite_back tests
revert hdf5 changes.
added doc comments for SqlStatement and Prepare. Changed /* comments to ///
changed sqlite3_close_v2 to sqlite3_close because v2 was added in 3.7.14 - newer than ci
removed throw in close - we expect close to fail sometimes if all prepared statements haven't been finalized yet
added a missing header
* fixed hdf5 problem - variable string for blob was being deallocated because hdf5 only stores ptr until flush
fixed hdf5 back doc comments