This commit serves as a temporary workaround for enabling the jit until
the block customisation PR is merged in.

Implemented the following block debugging RPC calls

* Block(RLP)
* BlockByFile(fileName)
* BlockByNumber(number)
* BlockByHash(hash)

The EVM is now initialised with an additional configured object that
allows you to turn on debugging options.

The EVM was previously initialised and created for every CALL, CALLCODE,
DELEGATECALL and CREATE. This PR changes this behaviour so that the same
EVM can be used through the session and beyond as long as the
Environment sticks around.

core: fixed various typos

core, eth: replace reorganiz with reorganis

core: various typos

eth: various typos

cmd/utils, internal/debug: fixes for debugging

templates: added issue template

p2p/nat: fix #2291, NAT discovery did't abort on failure

Go 1.6 only prints stacks for the current goroutine by default,
but for this panic we want to see all of them.

Setting runtime.MemProfileRate to 0 through the flag default
value makes it impossible to get an 'in-use' profile.

core: added future proc mutex lock

core: cache fresh headers and tds to avoid db trashing

Added a future lock which prevents the anything being added or removed
from or to the set when looping over the set of blocks. This fixes a nil
pointer in the range loop when trying to retrieve a block from the set
which was previously available but removed due to regular chain
processing.

Fixes #2305

Godeps: pull in the leveldb upstream write race fix

eth/downloader: fix a throughput estimation data race

core: create a header chain structure shared by full and light clients

core: announce ChainSideEvent during reorg

Godeps: update goleveldb to fix a compaction data race

cmd, eth, ethdb, node: prioritise chaindata for resources, bump cache

Previously all blocks that were already in our chain were never re
announced as potential uncle block (e.g. ChainSideEvent). This is
problematic during mining where you want to gather as much possible
uncles as possible increasing the profit. This is now addressed in this
PR where during reorganisations of chains the old chain is regarded as
uncles.

Fixed #2298

console: allow optional password on the command line

Godeps: pull in ethash future cache generator