Fixed exception when index didn't exist
Handle exception when column is already indexed
Merge pull request #2 from waveaccess/master

SNP Upload. Partial Expression/SNP Data upload. Postgres Expression data loading optimizations.
Refactoring for PlatformLoader
Support I2B2_PROCESS_SNP_DATA partial updates for PostgreSQL.Improve partial updates logic for I2B2_PROCESS_MRNA_DATA
Load meta info form platform file