use refactored awsv4 signatures/caching

Merge pull request #18 from SemanticSugar/use_erliam

use erliam for credential caching & request signing

Add support for update expressions

v1.0.5

Merge pull request #17 from SemanticSugar/LIQ-3577-add-support-for-up…

support querying in other regions

Merge pull request #16 from SemanticSugar/table_region_query

Support query/get in other regions

Hologram support; 10K max conns.

Merge pull request #10 from SemanticSugar/ten-k-max-conns

Update max connections count and dependencies.