* Add filters for pending transactions to RPC API
Allow filtering results in the parity_pendingTransaction endpoint as described in the API docs.
* Make arguments in parity_pendingTransactions work together
filter and limit
* fmt
* Requested changes
- filter in ethcore to avoid unneccessary copying
- rename gas_price to gasPrice
- implement requesting contract creation txs with "action"
* Some beautifying
Remove missing import and unneccessary dependency entry, add a comment
and set right lint level on new module
* fixed broken build after merge
* fmt
* fixing CI errors: type conversion
Co-authored-by: Karim Agha <karim.dev@gmail.com>