Documentation: fix API Specs

[ezdac]

The API specifications in the documentation don't seem to reflect the current status of the API properly:

e.g.

GET /api/1/channels

doesn't return:

Example Response
200 OK and

[
{
"sender_address" : "0x5601ea8445a5d96eeebf89a67c4199fbb7a43fbb",
"open_block" : "3241462",
"balance" : "0",
"deposit" : "10",
},
{
"sender_address" : "0x5176305093fff279697d3fc9b6bc09574303edb4",
"open_block" : "32654234",
"balance" : "0",
"deposit" : "25",
},
]

as stated in the docs,

but rather something like:

[
{
"blocks": [
3889952
],
"sender_address": "0x9185FE3c343CaD012407078998737dADB07E678D"
}
]