Merge pull request #13 from tcolar/master

Prevent panic when aptempting closing statement if statement is nill
Test nested unpack
Support for floats
Implement unpacking to addressable Complex values.
The Complex.Decode method also can return an error now.
Decode always receives a plain value
Test non-struct plain ComplexValue unpack
Add support for NULLs
Handle some unlikely edge cases
Merge pull request #19 from Hebo/add_null_support

Add support for NULLs
Fix integration test.
Merge pull request #17 from dnwade/master

Support for floats
prepare method was completely useless, also removed lru
Update README
Fix unique index test
Ignore sublime projects
Remove test scripts
New LRU implementation
The query must always be the same one
Disable LRU cache inside transactions
Option to change LRU size