merge changes from hbt4

See merge request !7

cleanup merge

See merge request !6

# Conflicts:
#   README.md

[DLN]  JussiInternal errors aren't always an http request, don't try to access log_traceback parameter when no http request. Comment out Gerlock's unfinished code that would report timing of a RequestTimeoutError and a ResponseTimeoutError

# Conflicts:
#   Pipfile
#   README.md
#   jussi/upstream.py
#   jussi/urn.py

Attach traceback in jussi interal error

See merge request !4

[DLN] add some comments and some commented-out code that logs broadcast_transaction_synchronous calls for traffic analysis

Change function of -2 caching (previously called DEFAULT_EXPIRE_IF_IRREVRESIBLE, now called EXPIRE IF REVERSIBLE). This caching is mainly used for caching blocks and block headers. Now irreversible blocks don't have an expiration time, so they only get evicted when the cache fills up. And the default expiration time for reversible blocks is 9s (EXTENDED_TTL)

Rename default namespace & update README

See merge request !5

Enabling this option will log traceback from exception.

Fix for key error when sending broadcast trx

See merge request !3

Fix for:
{"exception":"KeyError(0,)","message":"Internal Error","error_id":"65c8a0e4-ecd4-4424-a490-7f87cb0c889a","jrpc_request_id":1,"jussi_request_id":"001113248166147000","event":"Internal Error","logger":"jussi.errors","level":"error"}

while sending:
curl -s --data '{"jsonrpc":"2.0", "method":"network_broadcast_api.broadcast_transaction", "params":{"trx":{"ref_block_num":1097,"ref_block_prefix":2181793527,"expiration":"2016-03-24T18:00:21","operations":[{"type":"vote_operation","value":{"voter":"hiveio","author":"alice","permlink":"a-post-by-alice","weight":10000}}],"extensions":[],"signatures":[]},"max_block_age":50}, "id":1}' https://beta.openhive.network

 - Changed most variables from hard-coded export's, so that they only use their default value if
   the variable wasn't already set in the environment

 - Refactored most lines to follow shellscript standards, e.g. using `${}` where appropriate, quoting
   arguments and variables, etc.

 - Added some additional variables to make it easier to adjust individual portions of the docker tag
   through environment variables

 - Added basic information comment block to the top of the file explaining how to use the build script,
   and how to adjust the docker tag

 - Added a bash shebang and made the file executable

 - Added support for overriding the docker tag by passing an argument

 - Added `$DIR` variable, allowing `build.sh` to be ran from any working directory, without running
   into path context problems.

Fix build

See merge request !2

Community - adjust custom_json validator

update definition of invalid_broadcast_transaction for passing tests that should be failing in order to pass ;)

Example config file for using hivemind as a tags/follows replacement

Regex match on /proposals to route to steemd

Dont cache irreversible blocks forever

Fix ports in docker command

Ports should be 8080:8080, not 9000:9000

Fixes bug in which you cannot specify a port in the upstream config file