This reverts commit 2ecb7555.

Instead of building a full copy of a CTransaction being signed, and
then modifying bits and pieces until its fits the form necessary
for computing the signature hash, use a wrapper serializer that
only serializes the necessary bits on-the-fly.

This makes it easier to see which data is actually being hash,
reduces load on the heap, and also marginally improves performances
(around 3-4us/sigcheck here). The performance improvements are much
larger for large transactions, though.

The old implementation of SignatureHash is moved to a unit tests,
to test whether the old and new algorithm result in the same value
for randomly-constructed transactions.

This change moves test data into the binaries rather than reading them from
the disk at runtime.

Advantages:
- Tests become distributable
- Cross-compile friendly. Build on one machine and execute in an arbitrary
  location on another.
- Easier testing for backports. Users can verify that tests pass without having
  to track down corresponding test data.
- More trustworthy test results and easier quality assurance as tests make
  fewer assumptions about their environment.
- Tests could theoretically run at client/daemon startup and exit on failure.

Disadvantages:
- Required 'hexdump' build-dependency. This is a standard bsd tool that should
  be usable everywhere. It is likely already installed on all build-machines.
- Tests can no longer be fudged after build by altering test-data.

Bugfix: Since test_bitcoin is being built and run inside src/test/, try using relative directories from that point

Seems it was forgotten about when IsPushOnly() and the unittests were
written. A particular oddity is that OP_RESERVED doesn't count towards
the >201 opcode limit unlike every other named opcode.

These flags select features to be enabled/disabled during script
evaluation/checking, instead of several booleans passed along.
Currently these flags are defined:
* SCRIPT_VERIFY_P2SH: enable BIP16-style subscript evaluation
* SCRIPT_VERIFY_STRICTENC: enforce strict adherence to pubkey/sig encoding standards.

- Wiki says "block chain" is correct ;)
- remove some unneeded spaces I found in the source, while fixing the spelling

Only enabled inside tests for now.

Implement listunspent / getrawtransaction / createrawtransaction /
signrawtransaction, to support creation and
signing-on-multiple-device multisignature transactions.

so it takes a flag for how to interpret OP_EVAL.
Also increased IsStandard size of scriptSigs to 500 bytes, so
a 3-of-3 multisig transaction IsStandard.

OP_EVAL is a new opcode that evaluates an item on the stack as a script.
It enables a new type of bitcoin address that needs an arbitrarily
complex script to redeem.