Feature/upgrade standard token contract

[surabhil]

• Use EOSIO_DISPATCH instead of EOS_ABI
• Update contract to use symbol_code instead of symbol_name
• Use eosio replacement of account_name to name
• Explicitely use name.value to query in table as it converts name type to uint64_t
• Update multi indexes to the new format as per eosio
• Add class type (eosio::contract("ore.standard_token")) in the class definition
• Anotate all tables and actions with eosio::action/table for abi generation
• Add open and close actions as added in eosio.token contract in EOSIO/eoiso.contracts latest version
• Use TABLE and ACTION macros

[blackwatertepes]

LGTM, although, I'd wait for another Review, before merging.

[bas4r]

Looks good to me as well