Update of readme
Refactored to use composition for WorkbookSupport + some renaming
Added support for basic grid parsing
Eliminated Grid in favor of maintaing config on the parser

Forgot to delete Grid itself
Parsing now figures the no. of rows to pull in + pasing main methods + updated docs
Simplified workbook parsing + updated docs
Added spock test using where clause + bumped codenarc to 0.19
Added support for skipping columns + polishing + doc improvement
Added support for collecting details of data extraction errors
Added support for cobertura to build