Regroup smart contract methods

[dbadol]

A smart contract call at a given block height can use multiple methods.
The table display should somehow regroup (at least visually) these calls together. Either with some specific background color (alternating color for groups of calls), or maybe just a specific border over all the rows.

Example of how it is today, with some lines which should somehow be regrouped:

Example of how the experimental explorer display them (see the blue borders):

[dbadol]

Note: As those multiple methods belong to one single smart contract call, the filtering and sorting options (as per issue #7 ) should treat them as one single "row".

Example: