Move table manipulation functionality from table_plugin to tablelib

[vkocubinsky]

Currently table_plugin is responsible for delete column, swap columns, delete row, swap rows, insert separator, insert double separator, join lines, split lines.

This issue is about move this functionality into tablelib for more clear component responsibility, table_plugin primary responsible for get command from user and delegate command to tablelib

table = tablelib.TextTable(text, self.syntax)
table.swap_columns(1,2)
text = table.render()

[vkocubinsky]

Done