Performance Update

This PR gathers all the performance improvements. speed of pyard increased multiple fold. Faster startups.

Update for performance:

• aggressive caching for most used functions
• import pandas only during loading of data
• query for column
• remove use of regex for simple checks
• option to choose cache in batch

Refactor/cleanup:

• make methods private that do not need to be exposed
• wrap with try/catch all calls to load data